Manual Text--Pepsin

www.aladdin-e.com Address:800 S Wineville Avenue, Ontario, CA 91761,USA Website:www.aladdin-e.com Email USA: [email protected] Email EU: [email protected] Email Asia Pacific: [email protected] Manual Text--Pepsin I.U.B.: 3.4.23.1 methods including crystallization and C.A.S.: 9001-75-6 chromatography were further developed. Through Enzymatic Reaction: these methods, the amino acid sequences of pepsin and pepsinogen were determined (Tang 1973). Pepsin B and C were first isolated from porcine stomach by Ryle and Porter in 1959. As X-ray diffraction techniques improved through the mid-1970s, the three-dimensional structure of pepsin was determined, allowing for a better Pepsin is the principal proteolytic enzyme of understanding of the catalytic reaction (Fruton vertebrate gastric juice. Its inactive precursor form, 2002). pepsinogen, is produced in stomach mucosa. The Recently, interest in pepsin-type enzymes and minor pepsins are designated “B”, “C”, and “D”, their inhibitors has been renewed due to the while the major component is “A”, to which the recognition of HIV-protease as a member of this following data applies. aspartic protease family (Campos 2003). History: Specificity: Pepsin is of particular interest as it was the first Pepsin has broad specificity with a preference for enzyme to be discovered. The name pepsin was peptides containing linkages with aromatic or given by Theodor Schwann (1810-1882) in 1836, carboxylic L-amino acids. It preferentially cleaves and came from pepsis, the term for digestion in C-terminal to Phe and Leu and to a lesser extent Hippocratic writings. Into the mid-nineteenth Glu linkages. The enzyme does not cleave at Val, century, scientists showed that pepsin broke Ala, or Gly. down proteins into “peptones” (Fruton 2002). Composition: Pepsin was later found to be an effective Pepsin is a monomeric, two domain, mainly beta treatment for digestive disorders. Through this protein with a high percentage of acidic residues. important application, efforts to produce and Porcine pepsin has 4 basic residues, and 42 purify it greatly increased, and were successful by acidic residues and is O-phosphorylated at S68 the end of the nineteenth century (Tang 1998). (Tang et al. 1973). For the protein to be active, At that time, however, the chemical nature and one of the two aspartate residues in the catalytic properties of enzymes as proteins were not site has to be protonated, and the other completely understood. It was not until John H. deprotonated. This occurs between pH 1 and 5, Northrop crystallized pepsin in 1930, an and above pH 7 pepsin is irreversibly denatured. achievement for which he shared the Nobel Prize Molecular Characteristics: in 1946, that the protein nature of enzymes was The amino acid sequence of porcine pepsin was established (Manchester 2004). determined by Tang et al. (1973) and Moravek After the Nobel Prize was awarded to Northrop, and Kostka (1974), and later confirmed through Sumner, and Stanley in 1946, new separation 1 www.aladdin-e.com cDNA analysis by Tsukagoshi et al. (1988) and Protein Accession Number: P00791 Lin et al. (1989). CATH Classification (v. 3.2.0): The pepsinogen A (PGA) gene is divided among • Class: Mainly beta nine exons that encompass approximately 9.4 kb • Architecture: Beta Barrel of genomic DNA (Sogawa 1983). • Topology: Cathepsin D, subunit A; domain 1 There are multiple versions of the PGA genes Molecular weight: found in human and chimp populations, but the • Pepsin: 34.5 kDa (Theoretical) activities of these various gene products are • Pepsinogen: 41.4 kDa indistinguishable (Taggart 1985 and Zelle 1988). Optimal pH: 1.0-4.0 (At pH 1.5 pepsin exhibits In contrast, Southern blot analyses of a sampling about 90% of maximum activity, and at pH 4.5 of pigs suggest that there is only a about 35% of maximum activity. single PGAgene found in all pigs (Evers 1988). Isoelectric Point: 1.0 (Bovey and Yanari 1960) PGA production is mainly controlled at the Extinction Coefficient: transcription level (Sogawa et al. 1981 and • 49,650 cm-1 M-1 (Theoretical) Ichinose et al. 1988). In both humans and pigs, it • E1%,280 = 14.39 (Theoretical) has been found that the PGA gene is under Active Site Residues: tissue-specific transcriptional control, with mRNA • Aspartic acid (D32 and D215) only detected in gastric fundic mucosa (Ichinose Activators: 1991 and Meijerink et al. 1993). Transcription of • Pepsinogen the PGA gene is regulated by transcription- Inhibitors: activating proteins acting at 3 major regions in the • Aliphatic alcohols promoter and initiation regions of the PGA gene • Substrate-like epoxides (Meijerink et al. 1993). • Pepstatin A There are four reported pepsin proteins: pepsin A, Applications: pepsin B (parapepsin I), pepsin C (gastricsin), • and pepsin D (an unphosphorylated version of Digestion of antibodies pepsin A) (Lee and Ryle 1967). Pepsin A is the • Preparation of collagen for cosmeceutical predominant gastric protease; minor amounts of purposes the other pepsins have been detected. Pepsins B • Assessment of digestibility of proteins in food and C share a higher degree of homology with chemistry each other. In dog, B and C share 89% identity, A • Subculture of viable mammary epithelial cells and B share 44% identity, and A and C share (Riser 1983) 45% identity (calculated based on Thompson et al. 1994). 2 .

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