DOCSLIB.ORG

Whereas Trypsin Acts Almost Exclusively on Peptide Bonds

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Whereas Trypsin Acts Almost Exclusively on Peptide Bonds 884 BIOCHEMISTRY: WALSH AND NEURATH PROC. N. A. S. 22 Craig, L. G., W. Koenigsberg, and R. J. Hill, Amino Acids and Peptides with Antimetabolic Activity, CIBA Foundation Symposium (1958), p. 226. 23 Du Vigneaud, V., personal communication. 24 Mach, B., C. Slayman, and E. L. Tatum, manuscript in preparation. TRYPSINOGEN AND CHYMOTRYPSINOGEN AS HOMOLOGOUS PROTEINS BY KENNETH A. WALSH AND HANS NEURATH UNIVERSITY OF WASHINGTON, SEATFLE Communicated August 27, 1964 The striking similarity of many properties of trypsin and chymotrypsin has been well known for many years.1-5 Both enzymes originate in the acinar cells of pan- creatic tissue6 at identical rates7 as their inactive precursors trypsinogen and chymo- trypsinogen A, and both are activated by the cleavage (by trypsin) of the peptide bond contributed by the basic residue which is closest to the amino terminus of the zymogen.8, 9 Both enzymes catalyze the hydrolysis of peptide, amide, and ester bonds, and both are characterized by a high degree of selectivity toward the amino acids which donate carboxyl groups to these bonds.10-'2 In both cases, the enzymes appear to become acylated through these carboxyl groups as an intermediate step in the catalytic mechanism.."-"5 Both enzymes are inhibited by certain organic fluorophosphates such as DFP, 16 and the site of reaction of these inhibitors has been identified as a unique serine residue in the same tetrapeptide sequence.17' 18 The same serine residue becomes acylated as an intermediate in the catalytic mecha- nism."9 In addition to serine, a histidine residue has long been implicated as a componentof the active siteof both chymotrypsin and trypsin.20 Indirect supporting evidence, derived from the pH dependence of the acylation and deacylation steps, and from the effects of photooxidation on enzyme activation of chymotrypsin,2' has been recently strengthened and confirmed by the findings of Shaw and co- workers22-24 that bifunctional reagents, resembling in structure specific substrates, inactivate chymotrypsin and trypsin, respectively, by forming covalent derivatives of a single histidine residue in each enzyme. Chymotrypsinogen and trypsinogen resemble each other in certain chemical properties.1 These include molecular weights (approximately 25,000 and 24,000, respectively) and isoelectric points (approximately 9.3). A comparison of the amino acid compositions ofthe two zymogens25-27 in Table 1 revealsthat the similarity extends to this level also. The compositional similarity is made even more striking if certain residues of similar chemical character are grouped together, such as the total acidic, total basic, total aromatic, total branched hydrophobic, and total hydroxy-amino acid residues. Such comparative data are given at the bottom of Table 1. The only really striking difference between the two enzymes lies in their sub- strate specificity." Whereas trypsin acts almost exclusively on peptide bonds involving the carboxyl groups of lysine or arginine residues, chymotrypsin has no significant action upon these bonds, but is most active toward linkages involving the Downloaded by guest on September 29, 2021 VOL. 52, 1964 BIOCHEMISTRY: WALSH AND NEURATH 885 TABLE 1 AMINO ACID COMPOSITIONS OF TRYPSINOGEN26 AND CHYMOTRYPSINOGEN25 Trypsinogen Chymotrypsinogen Asparagine 16 14 Glutamine 11 10 Aspartic acid 10 9 Threonine 10 23 t Serine 33 29 Glutamic acid 3 5 Proline 9 9 Glycine 25 23 Alanine 14 22 Cystine/2 12 10 Valine 18 23 Methionine 2 2 Isoleucine 15 10 Leucine 14 19 Tyrosine 10 4 Phenylalanine 3 6 Tryptophan 4 8 Lysine 15 14 Histidine 3 2 Arginine 2 4 Total acidic residues 13 14 Lysine and arginine 17 18 Total amides 27 24 Total aromatic residues 17 18 Serine + threonine 43 52 Sum of isoleucine, leucine, and valine 47 52 carboxyl groups of aromatic amino acids. Althoughtrypsin also catalyzes the cleav- age of certain aromatic substrates (characteristic of chymotrypsin), it is less effec- tive than chymotrypsin in this regard, and far less effective than toward its own basic substrates. Several lines of evidence indicate that this property is intrinsic in trypsin itself, and not the result of a chymotryptic contamination.28 The recent finding of Mares-Guia and Shaw29 that a binding site for aromatic compounds ex- ists at the active center of trypsin indicates that the striking difference in specificity between the two enzymes may turn out to be a quantitative phenomenon, rather than a qualitative one, and draws attention again to the underlying similarity be- tween the two enzymes. The fundamental similarities in biological, mechanistic, and compositional char- acter between the two molecules have led to the logical prediction of an extensive similarity in primary structure,5 including in particular the regions of structure known to have functional importance. However, as the primary structure of the two molecules was evolved,30 no analogous amino acid sequences were found that were larger than the tetrapeptide sequence originally observed to surround the ser- ines of the active centers. More recently,3"-33 a nearly identical nonadecapeptide sequence was observed in chymotrypsin and trypsin containing two histidine resi- dues in sufficiently close proximity to each other to suggest that not one but both of them are functional components of the active center in both enzymes.26 The recent completion of the structure of chymotrypsinogen A25 and a tentative structure for trypsinogen27 31 permit a detailed comparison of the molecular struc- tures of the two enzymes, and a search for evidence of homology. This com- parison is made in Table 2 by outlining the linear structures of the two zymogens in such a fashion as to make in each the amino terminal isoleucine residue, formed Downloaded by guest on September 29, 2021 886 BIOCHEMISTRY: WALSH AND NEURATH PROC. N. A. S. TABLE 2 THE STRUCTURAL SIMILARITY OF TRYPSINOGEN AND CHYMOTRYPSINOGEN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Chymotrypsinogen cys-gly-val-pro-ala-ile-gln-pro-val-leu-ser-gly-leu-ser-arg-ILE-VAL-GLY- Trypsinogen val-asp-asp-asp-asp-lys-ILE-VAL-GLY- 1 2 3 4 5 6 7 8 9 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 asp-glu-glu-ala-val-pro-gly-ser-trp-PRO-trp-GLN-VAL-SER-LEU-gln-asp-lys-thr-GLY-phe-HIS-PHE- gly-tyr-thr-cys-gly-ala-asn-thr-val-PRO-tyr-GLN-VAL-SER-LEU-asn- -ser-GLY-tyr-HIS-PHE_ 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 CYS-GLY-GLY-SER-LEU-ILE-ASN-glu-asn-TRP-VAL-VAL-thr-AIA-ALA-HIS-CYS-gly-val-thr-thr-ser-asp- CYS-GLY-GLY-SER-LEU-ILE-ASN-ser-gln-TRP-VAL-VAL-ser-AIA-ALA-HIS-CYS-tyr-lys-ser-gly-ile-gln- 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 VAL-val-val-ala-gly-glu-phe-asp-gln-gly-ser-ser-ser-glu-lys-ile-gln-lys-leu-lys-ile-ala-lys- VAL-arg-leu-gly-glu-asp-asn-ile-asn-val-val-glu-gly-asp-glu-gln-phe-ile-ser-ala-ser-lys-ser- 54 55, 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 val-phe-lys-asn-SER-lys-TYR-ASN-ser-leu-thr-ile-ASN-ASN-asn-ILE-thr-LEU-leu-LYS-LEU-ser-thr- ile-val-his-pro-SER- -TYR-ASN(pro,leuthr,asn)ASN-ASN-asp-ILE-met-LEL-ile-LYS-LEU-lys-ser- 77 78 79 80 81 82 83 84 85 86 87 88 89 go 91 92 93 94 95 96 97 98 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 AIA-ALA-SER-phe-ser-gln-thr-VAL-ser-ala-val-cys-LEU-PRO-ser-ala-ser-asp-asp-phe-ala-AIA-GLY- AIA-ALA-SER-leu-asn-ser-arg-VAL-ala-ser-ile-ser-LEU-PRO-thr-ser-cys- -41a-ser-AIA-GLY- 99 100 101 102 103 104 105 106 107 108 109 11o 111 112 113 114 115 116 117 118 119 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 THR-thr-CYS-val-thr-thr-GLY-TRP-GLY-leu-THR-arg-tyr-thr-asn-ala-asn-thr-PRO-ASP-arg-LEU-gln- THR-gln-CYS-leu-ile-ser-GLY-TRP-GLY-asn-THR-lys-ser-ser-gly-thr-ser-tyr-PRO-ASP-val-LEU-lys- 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 157 158 159 160 161 162 165 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 gln-ala-ser-leu-PRO-leu-LEU-SER-asn-thr-asn-CYS-LYS-lys-tyr-trp-gly-thr-lys-ILE-lys-asp-ala- cys-leu-lys-ala-PRO-ile-LEU-SER-asp-ser-ser-CYS-LYS-ser-ala-tyr-pro-gly-gln-ILE-thr-ser-asn- 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 MET-ile-CYS-AIA-GLY-ala-ser-gly-val-ser- -SER-CYS-met-GLY-ASP-SER-GLY-GLY-PRO-leu-VAIL.
Load more

Recommended publications
  • Progress Report the Interrelationships of the Pancreatic Enzymes
    Gut: first published as 10.1136/gut.13.5.398 on 1 May 1972. Downloaded from Gut, 1972, 13, 398-412 Progress report The interrelationships of the pancreatic enzymes The quantitative interrelationships between the different functional types of pancreatic enzymes has been the subject of much experimental investiga- tion, but the results are conflicting and the inferences remain controversial. Recent improvements in techniques have provided new and more reliable means of measuring enzyme activities and it therefore seems pertinent to review the current state of knowledge about the factors which determine selective production of the pancreatic enzymes. Pavlovl, quoting the studies of his pupil Walther in dogs, described rapid 'adaptive' changes in the amounts of individual pancreatic enzymes secreted in response to changes in the predominant type of food in a single meal. Later studies supported Pavlov's hypothesis that the production of individual enzymes, or groups ofenzymes, could be selectively modified, but changed the emphasis by indicating that adaptation of pancreatic enzyme secretion might require prolonged dietary modification, for periods ranging from hours to weeks2'3'4. http://gut.bmj.com/ The converse hypothesis, that pancreatic enzymes were secreted 'in parallel', was proposed during the early years of the present century by Babkin5,6 on the basis of experiments in dogs with pancreatic fistulae and was later supported by studies of pancreatic secretion in other species, including man. In order to disentangle the current state of the evidence for the two on September 29, 2021 by guest. Protected copyright. conflicting hypotheses, the interrelationships between the pancreatic enzymes within the pancreatic-secreting cells, in the secreted juice, and within the small intestinal lumen are considered separately, since different factors determine the relative increase or decrease of individual enzymes or groups of enzymes in the three compartments.
    [Show full text]
  • Aandp2ch25lecture.Pdf
    Chapter 25 Lecture Outline See separate PowerPoint slides for all figures and tables pre- inserted into PowerPoint without notes. Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 Introduction • Most nutrients we eat cannot be used in existing form – Must be broken down into smaller components before body can make use of them • Digestive system—acts as a disassembly line – To break down nutrients into forms that can be used by the body – To absorb them so they can be distributed to the tissues • Gastroenterology—the study of the digestive tract and the diagnosis and treatment of its disorders 25-2 General Anatomy and Digestive Processes • Expected Learning Outcomes – List the functions and major physiological processes of the digestive system. – Distinguish between mechanical and chemical digestion. – Describe the basic chemical process underlying all chemical digestion, and name the major substrates and products of this process. 25-3 General Anatomy and Digestive Processes (Continued) – List the regions of the digestive tract and the accessory organs of the digestive system. – Identify the layers of the digestive tract and describe its relationship to the peritoneum. – Describe the general neural and chemical controls over digestive function. 25-4 Digestive Function • Digestive system—organ system that processes food, extracts nutrients, and eliminates residue • Five stages of digestion – Ingestion: selective intake of food – Digestion: mechanical and chemical breakdown of food into a form usable by
    [Show full text]
  • Hans Neurath 1909–2002
    Hans Neurath 1909–2002 A Biographical Memoir by Edmond H. Fischer and Earl W. Davie ©2013 National Academy of Sciences. Any opinions expressed in this memoir are those of the authors and do not necessarily reflect the views of the National Academy of Sciences. HANS NEURATH October 29,1909–April 2, 2002 Elected to the NAS, 1961 Hans Neurath, one of the foremost scientists of the 20th century and a man considered one of the founding fathers of modern protein science, passed away on Friday, April 2, 2002. He was the founding chairman of the Department of Biochemistry at the University of Washington School of Medicine in Seattle. After his administrative retirement as department chairman, he became the associate director of research at the Fred Hutchinson Cancer Research Center in Seattle and then, after reaching emeritus status at the University of Washington, he became director of the German Cancer Research Center in Heidelberg, Germany. By Edmond H. Fischer He returned to the University of Washington two years later. and Earl W. Davie Hans was the founding editor of Biochemistry, one of the most prestigious journals in the field and the flagship of some twenty journals published by the American Chemical Society. In 1992, at age 81, he founded Protein Science, a journal of the Protein Society, and he served as its editor-in-chief until 1998. Furthermore, he edited the most comprehensive treatise on proteins, The Proteins. Hans was an avid mountain climber and skier and a first-class pianist. He will be remembered as the person who contributed the most to the field of serine proteases and zymogen activation and, in collaboration with Bert Vallee, to the field of metallo- protein research.
    [Show full text]
  • Following Items. Toluene-Sulfonyl-L-Arginine Methyl
    TRYPTIC ACTIVATION OF ACETYLA TED CHYMOTRYPSINOGEN* BY A. K. BALLS AND C. A. RYAN WESTERN REGIONAL RESEARCH LABORATORY, ALBANY, CALIFORNIAt Communicated December 23, 1963 In a previous paper' we have reported on a rather heavily acetylated a-chymo- trypsinogen that could be activated by trypsin only in the presence of an electrolyte or, alternatively, by the action of unacetylated chymotrypsin prior to, or together with, that of trypsin. The present communication reports further observations on the preparation and composition of such an acetylated zymogen. The condi- tions for -suitable acetylation are different in the presence and in the absence of acetate. After acetylation the solution must be slightly acid, at least for a short time. It also appears that the activation of the acetylated protein in water is pre- vented because some form of acetylated chymotrypsinogen inhibits the action of trypsin on the acetylated zymogen in the absence of salts. This inhibitory ma- terial has been concentrated as a fraction of the mixture that constitutes the product of acetylation. Materials and Methods.-These have been previously described" 2 except for the following items. Trypsin was measured in the same manner as chymotrypsin. The substrate was toluene-sulfonyl-L-arginine methyl ester in 0.001 M tris-maleate buffer' at pH 7.5. The activity of C'4-labeled acetyl was measured in a liquid scintillation spec- trometer. Protein (ca. 0.5 mg) was dissolved in 0.01 N NaOH. The amount of water was limited to 0.2 ml or less in a system containing 15 ml of a fluorescent medium and about an equal volume of finely divided silica.4 Comparison with counts on the CO2 produced by combustion of the protein (which were estimated to be 95% efficient) indicated 48% efficiency in the foregoing system.
    [Show full text]
  • Enzyme Replacement Therapy for Pancreatic Insufficiency
    Enzyme replacement therapy for pancreatic insufficiency: present and future. Aaron Fieker, Jessica Philpott, Martine Armand To cite this version: Aaron Fieker, Jessica Philpott, Martine Armand. Enzyme replacement therapy for pancreatic insuffi- ciency: present and future.. Clinical and Experimental Gastroenterology, Dove Medical Press, 2011, 4 (4), pp.55-73. 10.2147/CEG.S17634. inserm-00701598 HAL Id: inserm-00701598 https://www.hal.inserm.fr/inserm-00701598 Submitted on 25 May 2012 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Clinical and Experimental Gastroenterology Dovepress open access to scientific and medical research Open Access Full Text Article RE VIEW Enzyme replacement therapy for pancreatic kpuwhÞekgpe{<"rtgugpv"cpf"hwvwtg Aaron Fieker1 Abstract: Pancreatic enzyme replacement therapy is currently the mainstay of treatment for Jessica Philpott1 nutrient malabsorption secondary to pancreatic insufficiency. This treatment is safe and has few Martine Armand2 side effects. Data demonstrate efficacy in reducing steatorrhea and fat malabsorption. Effective therapy has been limited by the ability to replicate the physiologic process of enzyme delivery 1Division of Digestive Diseases, University of Oklahoma, OKC, to the appropriate site, in general the duodenum, at the appropriate time. The challenges include OK, USA; 2INSERM, U476 enzyme destruction in the stomach, lack of adequate mixing with the chyme in the duodenum, “Nutrition Humaine et Lipides”, and failing to deliver and activate at the appropriate time.
    [Show full text]
  • The Digestive, Reproductive, and Urinary Systems
    The Digestive, Reproductive, and Urinary Systems THE DIGESTIVE SYSTEM Your body is constantly using energy, even when you’re at rest. Your cells use energy to carry out the normal functions of protein synthesis, cell maintenance and repair, and their own particular functions. On a larger scale, processes such as breathing, pumping of the heart, maintenance of normal levels of substances within the body, and digestion and absorption of foods are vital to life. All these processes continue while you’re sleeping. Because your body can’t man- ufacture energy, it must obtain that energy from elsewhere. In all animals, energy comes from food. Food also provides the body with fresh raw materials for growth, maintenance, and repair of body structures. The digestive system deals with the intake, physical breakdown, chemical digestion, and absorption of food, along with the elimination of waste products created by this process. The digestive system also eliminates certain toxic substances and secretes hormones it uses to regulate itself. The Oral Cavity The mouth, or oral cavity, consists of the lips, teeth and gums, tongue, oropharynx, and the associated salivary glands. The lips are a zone of transition from the skin of the face to the mucous membrane (a general term denoting the surface of an organ lubricated by moisture) lining the gums and the inside of your cheeks. Several layers of muscle help the lips grab and retain food and water within the mouth. 1 Different animals have different degrees of lip muscle devel- opment. Grazing animals like cattle, sheep, and horses have muscular lips that are prehensile (i.e., adapted to grasp plant material).
    [Show full text]
  • Digestion and Absorption Use of Physico-Chemical Concepts and Techniques
    UNIT 5 HUMAN PHYSIOLOGY Chapter 16 The reductionist approach to study of life forms resulted in increasing Digestion and Absorption use of physico-chemical concepts and techniques. Majority of these studies employed either surviving tissue model or straightaway cell- Chapter 17 free systems. An explosion of knowledge resulted in molecular biology. Breathing and Exchange Molecular physiology became almost synonymous with biochemistry of Gases and biophysics. However, it is now being increasingly realised that neither a purely organismic approach nor a purely reductionistic Chapter 18 molecular approach would reveal the truth about biological processes Body Fluids and or living phenomena. Systems biology makes us believe that all living Circulation phenomena are emergent properties due to interaction among components of the system under study. Regulatory network of molecules, Chapter 19 supra molecular assemblies, cells, tissues, organisms and indeed, Excretory Products and populations and communities, each create emergent properties. In the their Elimination chapters under this unit, major human physiological processes like digestion, exchange of gases, blood circulation, locomotion and Chapter 20 movement are described in cellular and molecular terms. The last two Locomotion and Movement chapters point to the coordination and regulation of body events at the organismic level. Chapter 21 Neural Control and Coordination Chapter 22 Chemical Coordination and Integration 2021-22 ALFONSO CORTI, Italian anatomist, was born in 1822. Corti began his scientific career studying the cardiovascular systems of reptiles. Later, he turned his attention to the mammalian auditory system. In 1851, he published a paper describing a structure located on the basilar membrane of the cochlea containing hair cells that convert sound vibrations into nerve impulses, the organ of Corti.
    [Show full text]
  • Chapter 17: Digestive System Test 1. Which Intestinal Layer Accounts For
    Chapter 17: Digestive System Test 1. Which intestinal layer accounts for the action of the peristaltic waves? A) serosa B) muscularis C) submucosa D) mucous 2. The alimentary tube is around _____ meters long. A) 2 B) 4 C) 6 D) 9 3. The _____ nervous system division usually stimulates and promotes digestion. A) somatic B) sympathetic C) central D) parasympathetic 4. The processes of chewing are referred to as _____. A) churning B) mastication C) peristalsis D) deglutition 5. Gastric enzymes are secreted by the _____ cells. A) chief B) goblet C) parietal D) oxyntic 6. Proteins are digested or broken down by the _____ in the stomach. A) pepsinogen B) pepsin C) hydrochloric acid D) lipase 7. Parasympathetic stomach impulses cause all of the following except which one? A) secretion of somatostatin B) inhibition of somatostatin C) secretion of gastrin D) promotes histamine 8. Gastrin secretion will stop when the stomach pH reaches _____. A) 7.0 B) 4.5 C) 1.5 D) 3.0 9. The alkaline tide occurs when _____ is secreted into the blood. A) HCl B) H+ C) bicarbonate ions D) phosphate ions 10. The _____ duct directly receives the fluids from the gallbladder. A) cystic B) common bile C) hepatic D) common hepatic 11. The common bile duct is formed by the merger of the hepatic and _____ ducts. A) common hepatic B) cystic C) pancreatic D) Santorini 12. The ampulla of Vater is the area that joins the common bile duct to the _____ duct. A) hepatic B) pancreatic C) cystic D) common hepatic 13.
    [Show full text]
  • Serine Proteases Enrico Di Cera Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Box 8231, St
    IUBMB Life, 61(5): 510–515, May 2009 Critical Review Serine Proteases Enrico Di Cera Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Box 8231, St. Louis, MO, USA the serine protease fold especially evident in the trypsins. This Summary new dimension changes our understanding of serine protease Over one third of all known proteolytic enzymes are serine function, regulation, and specificity. proteases. Among these, the trypsins underwent the most pre- dominant genetic expansion yielding the enzymes responsible for digestion, blood coagulation, fibrinolysis, development, fer- tilization, apoptosis, and immunity. The success of this expan- GENERAL PROPERTIES OF SERINE PROTEASES sion resides in a highly efficient fold that couples catalysis and Barrett and coworkers have devised a classification scheme regulatory interactions. Added complexity comes from the recent observation of a significant conformational plasticity of based on statistically significant similarities in sequence and the trypsin fold. A new paradigm emerges where two forms of structure of all known proteolytic enzymes and term this data- the protease, E* and E, are in allosteric equilibrium and deter- base MEROPS (8). The classification system divides proteases mine biological activity and specificity. Ó 2009 IUBMB into clans based on catalytic mechanism and families on the ba- IUBMB Life, 61(5): 510–515, 2009 sis of common ancestry. Over one third of all known proteolytic enzymes are serine proteases grouped into 13 clans and 40 fam- Keywords serine proteases; enzyme catalysis; thrombin; allostery. ilies. The family name stems from the nucleophilic Ser in the enzyme active site, which attacks the carbonyl moiety of the substrate peptide bond to form an acyl-enzyme intermediate (4).
    [Show full text]
  • Evidence for the Amino Acid Sequence of Porcine Pancreatic Elastase by DAVID M
    Biochem. J. (1973) 131, 643-675 643 Printed in Great Britain Evidence for the Amino Acid Sequence of Porcine Pancreatic Elastase By DAVID M. SHOTTON* and BRIAN S. HARTLEY Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, U.K. (Received 7 Aulgust 1972) The preparation and purification of tryptic peptides from aminoethylated Dip-elastase and [14C]carboxymethylated Dip-elastase, and of peptic peptides from native elastase is described. A summary of the results of chemical studies used to elucidate the amino acid sequence of these peptides is presented. Full details are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50016 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 1-20. These results, together with those from previously published papers, are used to establish the complete amino acid sequence of elastase, which is a single polypeptide chain of 240 residues, molecular weight 25900, containing four disulphide bridges. Hartley et al. (1959) and Naughton et al. (1960) cystine diagonal technique of Brown & Hartley first investigated the amino acid sequence of porcine (1966). [To aid comparison of the amino acid pancreatic elastase (EC 3.4.4.7) and proved that the sequence of elastase with those of other pancreatic enzyme was homologous with bovine trypsin and serine proteinases, we have used the chymotrypsino- chymotrypsin-A, possessing the -Asp-Ser-Gly- active- gen-A numbering scheme to describe the position of centre sequence characteristic of this class of serine amino acid residues in the elastase polypeptide chain; proteinases (Hartley, 1960).
    [Show full text]
  • The Evolution, Gene Expression Profile, and Secretion of Digestive
    catalysts Article The Evolution, Gene Expression Profile, and Secretion of Digestive Peptidases in Lepidoptera Species 1, 2,3, 2 2 2 Lucas R. Lima y , Renata O. Dias y, Felipe Jun Fuzita , Clélia Ferreira , Walter R. Terra and Marcio C. Silva-Filho 1,4,* 1 Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Mato Grosso do Sul 79117-010, Brazil; [email protected] 2 Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo 05508-000, Brazil; [email protected] (R.O.D.); [email protected] (F.J.F.); [email protected] (C.F.); [email protected] (W.R.T.) 3 Departamento de Genética, Universidade Federal de Goiás, Goiânia, Goiás 74690-900, Brazil 4 Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, São Paulo 13418-900, Brazil * Correspondence: [email protected]; Tel.: +55-19-3429-4442 These authors contributed equally to this work. y Received: 6 January 2020; Accepted: 6 February 2020; Published: 11 February 2020 Abstract: Serine peptidases (SPs) are responsible for most primary protein digestion in Lepidoptera species. An expansion of the number of genes encoding trypsin and chymotrypsin enzymes and the ability to upregulate the expression of some of these genes in response to peptidase inhibitor (PI) ingestion have been associated with the adaptation of Noctuidae moths to herbivory. To investigate whether these gene family expansion events are common to other Lepidoptera groups, we searched for all genes encoding putative trypsin and chymotrypsin enzymes in 23 publicly available genomes from this taxon.
    [Show full text]
  • Digestion and Absorption
    © shotty/Shutterstock. CHAPTER 2 Digestion and Absorption ← HERE’S WHERE YOU HAVE BEEN 1. The basic unit of human life is the cell, which operates independently and in concert with other cells to sustain human life. 2. There are approximately 200 different types of cells in the human body, each one with different roles and nutrient requirements. 3. Cell structural and operational components have specialized functions that affect nutrient processing, storage, and requirements. 4. Many nutrients play a role in protein synthesis by influencing gene expression or various steps in protein manufacturing. 5. Proteins have many specialized functions, including serving as enzymes, transporters, receptors, and hormones. HERE’S WHERE YOU ARE GOING → 1. Digestion is a complex synergy of the physical actions of chewing, mixing, and movement and the chemical actions of acids, enzymes, and detergent-like emulsifiers. 2. Absorption refers to the movement of nutrients from the digestive tract into the blood or lymphatic circulation, whereas the concept of bioavailability also includes the uptake and use of a nutrient by cells or tissue. 3. Perceptions of hunger and satiety involve multiple hormonal and neurologic signals, including cholecystokinin, neuropeptide Y, ghrelin, obestatin, insulin, and leptin. 4. Different types of bacteria are found throughout the entire digestive tract; the specific conditions of the different segments (e.g., mouth, stomach, colon) determine which species will thrive. 35 36 Chapter 2 Digestion and Absorption ▸ (FIGURE 2.1). The gastrointestinal tract, or simply “the Introduction gut,” and several organs (the salivary glands, pancreas, With the exception of intravenous infusion, nutrient liver, and gallbladder) that empty supportive substances entry into the body takes place by way of the gastro- into the gut make up the gastrointestinal system.
    [Show full text]