Chemistry and Functions of Hemoglobin and Myoglobin
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18,8 Quaternary Structure of Proteins
570 CHAPTERt8 Amino Acids,Peptides, and Proteins 18,8Quaternary structure of proteins AIMS: Todefine the termssubunit dnd quaternarystructure. Io describethe quoternorystructure of hemoglobin.To distinguishomong oxyhemoglobin,deoxyhemoglobin, ond methemoglobin. Someproteins consist of more than one pollpeptide chain. Theseindiuid- ual chains are calledsubunits of the protein. Proteins composedof subunits In some proteins, polypeptide are said to haue quaternary structure. Many proteins have structures that chains aggregateto form contain subunits. Proteins consistingof dimers (two subunits), tetramers quaternary structures. (four subunits), and hexamers (six subunits) are fairly common. The pro- teins that comprise the individual subunits may be identical, or they may be different. Like the secondary and tertiary structures, the quaternary structure of a protein is determined by its primary structure. The pollpep- tide chains of subunits are held in place by the same forces that determine tertiary structure-hydrogen bonds, salt bridges, and sometimes disulfide bridges-except the forces are betweenthe polypeptide chains of the sub- units instead of within them. Hydrophobic aliphatic and aromatic side chains of subunits can aggregateto exclude water. Hemoglobin-the globular oxygen-transport protein of blood-is an example of a protein that has a quaternary structure. Max Perutz, also of the Medical ResearchCouncil laboratories,determined the structure of horse blood hemoglobin in 1959.Hemoglobin is a larger molecule than myoglo- bin. The hemoglobin molecule has a molar mass of 64,500.It contains about 5000 individual atoms, excluding hydrogens, in 574 amino acid residues. The quaternary structure of hemoglobin consistsof four peptide sub- units. TWo of the subunits are identical and are called the alpha subunits. -
The Evolution of Hemoglobin. by Ross Hardison
American Scientist March-April 1999 v87 i2 p126(1) Page 1 the evolution of hemoglobin. by Ross Hardison A comparative study of hemoglobin was conducted to explain how an ancestral single-function molecule gave rise to descending molecules with varied functions. Hemoglobin is the molecule in red blood cells responsible for giving blood its color and for carrying oxygen throughout the body. New functions of metallo-porphyrin rings or a kind of molecular cage embedded in proteins were developed with the appearance of atmospheric oxygen. The presence of hemoglobin in both oxygen-needing and non-oxygen needing organisms suggests the same evolutionary roots. © COPYRIGHT 1999 Sigma Xi, The Scientific Research If similar compounds are used in all of these reactions, Society then how do the different functions arise? The answer lies in the specific structure of the organic component, most Studies of a very ancient protein suggest that changes in often a protein, that houses the porphyrin ring. The gene regulation are an important part of the evolutionary configuration of each protein determines what biochemical story service the protein will perform. The appearance of atmospheric oxygen on earth between Because they have such an ancient lineage, the one and two billion years ago was a dramatic and, for the porphyrin-containing molecules provide scientists with a primitive single-celled creatures then living on earth, a rare opportunity to follow the creation of new biological potentially traumatic event. On the one hand, oxygen was compounds from existing ones. That is, how does an toxic. On the other hand, oxygen presented opportunities ancestral molecule with a single function give rise to to improve the process of metabolism, increasing the descendant molecules with varied functions? In my efficiency of life’s energy-generating systems. -
Human Physiology an Integrated Approach
Gas Exchange and Transport Gas Exchange in the Lungs and Tissues 18 Lower Alveolar P Decreases Oxygen Uptake O2 Diff usion Problems Cause Hypoxia Gas Solubility Aff ects Diff usion Gas Transport in the Blood Hemoglobin Binds to Oxygen Oxygen Binding Obeys the Law of Mass Action Hemoglobin Transports Most Oxygen to the Tissues P Determines Oxygen-Hb Binding O2 Oxygen Binding Is Expressed As a Percentage Several Factors Aff ect Oxygen-Hb Binding Carbon Dioxide Is Transported in Three Ways Regulation of Ventilation Neurons in the Medulla Control Breathing Carbon Dioxide, Oxygen, and pH Infl uence Ventilation Protective Refl exes Guard the Lungs Higher Brain Centers Aff ect Patterns of Ventilation The successful ascent of Everest without supplementary oxygen is one of the great sagas of the 20th century. — John B. West, Climbing with O’s , NOVA Online (www.pbs.org) Background Basics Exchange epithelia pH and buff ers Law of mass action Cerebrospinal fl uid Simple diff usion Autonomic and somatic motor neurons Structure of the brain stem Red blood cells and Giant liposomes hemoglobin of pulmonary Blood-brain barrier surfactant (40X) From Chapter 18 of Human Physiology: An Integrated Approach, Sixth Edition. Dee Unglaub Silverthorn. Copyright © 2013 by Pearson Education, Inc. All rights reserved. 633 Gas Exchange and Transport he book Into Thin Air by Jon Krakauer chronicles an ill- RUNNING PROBLEM fated trek to the top of Mt. Everest. To reach the summit of Mt. Everest, climbers must pass through the “death zone” T High Altitude located at about 8000 meters (over 26,000 ft ). Of the thousands of people who have attempted the summit, only about 2000 have been In 1981 a group of 20 physiologists, physicians, and successful, and more than 185 have died. -
The Role of Methemoglobin and Carboxyhemoglobin in COVID-19: a Review
Journal of Clinical Medicine Review The Role of Methemoglobin and Carboxyhemoglobin in COVID-19: A Review Felix Scholkmann 1,2,*, Tanja Restin 2, Marco Ferrari 3 and Valentina Quaresima 3 1 Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland 2 Newborn Research Zurich, Department of Neonatology, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland; [email protected] 3 Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy; [email protected] (M.F.); [email protected] (V.Q.) * Correspondence: [email protected]; Tel.: +41-4-4255-9326 Abstract: Following the outbreak of a novel coronavirus (SARS-CoV-2) associated with pneumonia in China (Corona Virus Disease 2019, COVID-19) at the end of 2019, the world is currently facing a global pandemic of infections with SARS-CoV-2 and cases of COVID-19. Since severely ill patients often show elevated methemoglobin (MetHb) and carboxyhemoglobin (COHb) concentrations in their blood as a marker of disease severity, we aimed to summarize the currently available published study results (case reports and cross-sectional studies) on MetHb and COHb concentrations in the blood of COVID-19 patients. To this end, a systematic literature research was performed. For the case of MetHb, seven publications were identified (five case reports and two cross-sectional studies), and for the case of COHb, three studies were found (two cross-sectional studies and one case report). The findings reported in the publications show that an increase in MetHb and COHb can happen in COVID-19 patients, especially in critically ill ones, and that MetHb and COHb can increase to dangerously high levels during the course of the disease in some patients. -
Chemistry and Functions of Proteins
TVER STATE MEDICAL UNIVERSITY BIOCHEMISTRY DEPARTMENT CHEMISTRY AND FUNCTIONS OF PROTEINS ILLUSTRATED BIOCHEMISTRY Schemes, formulas, terms and algorithm of preparation The manual for making notes of lectures and preparation for classes Tver, 2018 AMINO ACIDS -amino acids -These are organic acids with at least a minimum of one of its hydrogen atoms in the carbon chains substituted by an amino group.( Show the radical, amino and carboxyl groups) NH2 R | C – H | COOH Proteinogenous and Nonproteinogenous Amino acids - Major proteinogenous (standard) amino acids. (Give the names of each amino acid) R R 1 H – 2 CH3 – 12 HO – CH2 – (CH3)2 CH – 3 CH3 – CH – (CH3)2 CH – CH2 – 4 13 | CH3 – CH2 – CH – OH 5 | CH 3 6 14 HS – CH2 – HOOC – CH2 – 15 CH3 – S – CH2 – CH2 – 7 HOOC – CH2 – CH2 – NH2 | – C – H - | COOH 8 16 NH2 – CO – CH2 – 9 NH2 – CO – CH2 – CH2 – 17 10 NH2 – (CH2)3 – CH2 – 18 NH2 – C – NH – (CH2)3 – CH2 – 11 || NH 19 20 СООН NH -Glycine -Arginine Alanine -Serine -Valine -Threonine Leucine -Cysteine Isoleucine -Methionine Aspartic acid -Phenylalanine Glutamic acid -Tyrosine Asparagine -Tryptophan Glutamine -Histidine Lysine -Proline •Rare proteinogenous (standard) amino acids. ( Derivatives of lysine, proline and tyrosine) NH2 | H2N – CH2 – CH – (CH2)2 – CH | | OH COOH •Nonproteinogenous amino acids. (Name and show them) NH2 NH2 | | H2N – (CH2)3 – CH HS – (CH2)2 – CH | | COOH COOH NH2 | NH2 – C – HN – (CH2)3 – CH || | O COOH Ornithine Homocysteine Citrulline 2 CLASSIFICATION OF PROTEINOGENOUS (STANDARD) AMINO ACIDS Amino acids are classified by: *The structure of the radical (show); - aliphatic amino acids -monoaminodicarboxylic amino acids -amides of amino acids -diaminomonocarboxylic amino acids -hydroxy amino acids -sulfur-containing amino acids -cyclic (aromatic and heterolytic) amino acids *the polarity of the radical (show); -Non-polar (hydrophobic –Ala, Val, Leu, Ile, Trp, Pro.) -Polar (hydrophilic). -
Hemoglobin, Myoglobin and Neuroglobin in Endogenous Thiosulfate Production Processes
International Journal of Molecular Sciences Review The Role of Hemoproteins: Hemoglobin, Myoglobin and Neuroglobin in Endogenous Thiosulfate Production Processes Anna Bilska-Wilkosz *, Małgorzata Iciek, Magdalena Górny and Danuta Kowalczyk-Pachel Chair of Medical Biochemistry, Jagiellonian University Collegium Medicum ,7 Kopernika Street, Kraków 31-034, Poland; [email protected] (M.I.); [email protected] (M.G.); [email protected] (D.K.-P.) * Correspondence: [email protected]; Tel.: +48-12-4227-400; Fax: +48-12-4223-272 Received: 5 May 2017; Accepted: 16 June 2017; Published: 20 June 2017 Abstract: Thiosulfate formation and biodegradation processes link aerobic and anaerobic metabolism of cysteine. In these reactions, sulfite formed from thiosulfate is oxidized to sulfate while hydrogen sulfide is transformed into thiosulfate. These processes occurring mostly in mitochondria are described as a canonical hydrogen sulfide oxidation pathway. In this review, we discuss the current state of knowledge on the interactions between hydrogen sulfide and hemoglobin, myoglobin and neuroglobin and postulate that thiosulfate is a metabolically important product of this processes. Hydrogen sulfide oxidation by ferric hemoglobin, myoglobin and neuroglobin has been defined as a non-canonical hydrogen sulfide oxidation pathway. Until recently, it appeared that the goal of thiosulfate production was to delay irreversible oxidation of hydrogen sulfide to sulfate excreted in urine; while thiosulfate itself was only an intermediate, transient metabolite on the hydrogen sulfide oxidation pathway. In the light of data presented in this paper, it seems that thiosulfate is a molecule that plays a prominent role in the human body. Thus, we hope that all these findings will encourage further studies on the role of hemoproteins in the formation of this undoubtedly fascinating molecule and on the mechanisms responsible for its biological activity in the human body. -
Adult, Embryonic and Fetal Hemoglobin Are Expressed in Human Glioblastoma Cells
514 INTERNATIONAL JOURNAL OF ONCOLOGY 44: 514-520, 2014 Adult, embryonic and fetal hemoglobin are expressed in human glioblastoma cells MARWAN EMARA1,2, A. ROBERT TURNER1 and JOAN ALLALUNIS-TURNER1 1Department of Oncology, University of Alberta and Alberta Health Services, Cross Cancer Institute, Edmonton, AB T6G 1Z2, Canada; 2Center for Aging and Associated Diseases, Zewail City of Science and Technology, Cairo, Egypt Received September 7, 2013; Accepted October 7, 2013 DOI: 10.3892/ijo.2013.2186 Abstract. Hemoglobin is a hemoprotein, produced mainly in Introduction erythrocytes circulating in the blood. However, non-erythroid hemoglobins have been previously reported in other cell Globins are hemo-containing proteins, have the ability to types including human and rodent neurons of embryonic bind gaseous ligands [oxygen (O2), nitric oxide (NO) and and adult brain, but not astrocytes and oligodendrocytes. carbon monoxide (CO)] reversibly. They have been described Human glioblastoma multiforme (GBM) is the most aggres- in prokaryotes, fungi, plants and animals with an enormous sive tumor among gliomas. However, despite extensive basic diversity of structure and function (1). To date, hemoglobin, and clinical research studies on GBM cells, little is known myoglobin, neuroglobin (Ngb) and cytoglobin (Cygb) repre- about glial defence mechanisms that allow these cells to sent the vertebrate globin family with distinct function and survive and resist various types of treatment. We have tissue distributions (2). During ontogeny, developing erythro- shown previously that the newest members of vertebrate blasts sequentially express embryonic {[Gower 1 (ζ2ε2), globin family, neuroglobin (Ngb) and cytoglobin (Cygb), are Gower 2 (α2ε2), and Portland 1 (ζ2γ2)] to fetal [Hb F(α2γ2)] expressed in human GBM cells. -
Structure and Function of Leghemoglobins*
203 Structure and function of leghemoglobins* by M. BECANA**, J.F. MORAN, I. ITURBE-ORMAETXE, Y. GOGORCENA and P.R. ESCUREDO Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei (C.S.I.C.), Apartado 202, 50080 Zaragoza Received: 31-10-1994 Key words: Free radicals, Iron, Leghemoglobins, Nitrogen fixation, Oxygen, Plant senescence, Root nodules. Abbreviation: Lb, leghemoglobin. ABSTRACT Becana, M., Moran, J.F., Iturbe-Ormaetxe, I., Gogorcena, Y. and Escuredo, P.R. 1995. Structure and function of leghemoglobins. An. Estac. Exp. Aula Dei (Zaragoza) 21(3): 203-208. Leghemoglobin (Lb) is a myoglobin-like protein of about 16 kDa, which occurs in legume root nodules at very high concentra - tions. Usually the heme moiety is synthesized by the bacteroids but mitochondria may provide also heme for Lb when bacteria are defective in heme production or perhaps when Lb is produced in uninfected cells of nodules. Lb plays an essential role in the nitro - gen fixation process, by providing oxygen to the bacteroids at a low, but constant, concentration, which allows for simultaneous bac - teroid respiration and nitrogenase activity. Lb must be in the reduced, ferrous state to carry oxygen. Several factors within the nodu - les are conducive for Lb oxidation to its ferric, inactive form. During these inactivation reactions free radicals are generated. Howe - ver, healthy nodules contain around 80% of ferrous Lb and 20% of oxyferrous Lb, but not ferric Lb, which indicates that mechanisms exist in the nodules to maintain Lb reduced; these are the enzyme ferric Lb reductase and free flavins. Lb degradation is a largely unk - nown process, but several intermediates with modified hemes,presumably by oxidative attack,have been encountered, including modi - fied Lbam, choleglobin, and biliverdin. -
Absolute Measurements of Cerebral Perfusion and Oxygenation in Rats with Near-Infrared Spectroscopy Bertan Hallacoglu1, Angelo Sassaroli1, Irwin H
Absolute measurements of cerebral perfusion and oxygenation in rats with near-infrared spectroscopy Bertan Hallacoglu1, Angelo Sassaroli1, Irwin H. Rosenberg2, Aron Troen2 and Sergio Fantini1 Tufts University Department of Biomedical Engineering, Medford, MA (1) and USDA Human Nutrition Research Center on Aging, Boston, MA (2) Brain microvascular pathology is a common finding in Alzheimer’s disease and other dementias. However, Figure 2 – Time traces of [Hb], [HbO2], [HbT], StO2 and SaO2 during the hypoxia and hypercapnia protocols 10 and 20 weeks after Figure 3 – Illustration of the differences in animal groups and the extent to which microvascular abnormalities cause or contribute to cognitive impairment is unclear. the start of folate deficient diet (blue and red lines represent the mean values for each dietary group, whereas, dashed lines indicate changes within each group between weeks 10 and 20 in Dietary vascular risk factors, including poor folate status are potentially modifiable predictors of cognitive the range corresponding to ± one standard error from the mean). A first striking result is the consistency of baseline values across cerebral tissue saturation (StO2) and concentration of impairment among older adults. Folate deficiency in rat impairs cognition and causes cerebral animals within a group (control or folate deficient), and the reproducibility of baseline values measured at weeks 10 and 20. hemoglobin ([HbT]), blood concentration of hemoglobin ([HbT]b), microvascular damage, without concomitant neurodegeneration [1]. We hypothesized that folate Absolute brain total hemoglobin concentration ([HbT]) and tissue oxygen saturation (StO2) are significantly reduced by folate and partial blood volume (Vb/Vt) Eq. (1). FD rats have deficiency might result in functional decrements in cerebral oxygen delivery and vascular reactivity. -
The Effects of Temperature on Hemoglobin in Capitella Teleta
THE EFFECTS OF TEMPERATURE ON HEMOGLOBIN IN CAPITELLA TELETA by Alexander M. Barclay A thesis submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Master of Science in Marine Studies Summer 2013 c 2013 Alexander M. Barclay All Rights Reserved THE EFFECTS OF TEMPERATURE ON HEMOGLOBIN IN CAPITELLA TELETA by Alexander M. Barclay Approved: Adam G. Marsh, Ph.D. Professor in charge of thesis on behalf of the Advisory Committee Approved: Mark A. Moline, Ph.D. Director of the School of Marine Science and Policy Approved: Nancy M. Targett, Ph.D. Dean of the College of Earth, Ocean, and Environment Approved: James G. Richards, Ph.D. Vice Provost for Graduate and Professional Education ACKNOWLEDGMENTS I extend my sincere gratitude to the individuals that either contributed to the execution of my thesis project or to my experience here at the University of Delaware. I would like to give special thanks to my adviser, Adam Marsh, who afforded me an opportunity that exceeded all of my prior expectations. Adam will say that I worked very independently and did not require much guidance, but he served as an inspiration and a role model for me during my studies. Adam sincerely cares for each of his students and takes the time and thought to tailor his research program to fit each person's interests. The reason that I initially chose to work in Adam's lab was that he expressed a genuine excitement for science and for his lifes work. His enthusiasm resonated with me and helped me to find my own exciting path in science. -
Chain of Human Neutrophil Cytochrome B CHARLES A
Proc. Nati. Acad. Sci. USA Vol. 85, pp. 3319-3323, May 1988 Biochemistry Primary structure and unique expression of the 22-kilodalton light chain of human neutrophil cytochrome b CHARLES A. PARKOS*, MARY C. DINAUERt, LESLIE E. WALKER*, RODGER A. ALLEN*, ALGIRDAS J. JESAITIS*, AND STUART H. ORKINtt *Department of Immunology, Research Institute of the Scripps Clinic, La Jolla, CA 92037; tDivision of Hematology-Oncology, Children's Hospital, and Dana-Farber Cancer Institute, Department of Pediatrics, Harvard Medical School, Boston, MA 02115; and tHoward Hughes Medical Institute, Children's Hospital, Boston, MA 02115 Communicated by Harvey F. Lodish, January 14, 1988 ABSTRACT Cytochrome b comprising 91-kDa and 22- Cytochrome b purified from neutrophil membranes ap- kDa subunits is a critical component of the membrane-bound pears to be a heterodimer of a glycosylated 91-kDa heavy oxidase of phagocytes that generates superoxide. This impor- chain and a nonglycosylated 22-kDa light chain (10-12). The tant microbicidal system is impaired in inherited disorders 91-kDa subunit is encoded by a gene designated CGD, known as chronic granulomatous disease (CGD). Previously we residing at chromosomal position Xp2l, which originally was determined the sequence of the larger subunit from the cDNA identified on the basis of genetic linkage without reference to of the CGD gene, the X chromosome locus affected in "X- a specific protein product (8). Antisera generated to either a linked" CGD. To complete the primary structure of the synthetic peptide predicted from the cDNA or to a fusion cytochrome b and to assess expression of the smaller subunit, protein produced in E. -
The Effect of Anemia on the Ventilatory Response to Transient and Steady-State Hypoxia
The effect of anemia on the ventilatory response to transient and steady-state hypoxia. T V Santiago, … , N H Edelman, A P Fishman J Clin Invest. 1975;55(2):410-418. https://doi.org/10.1172/JCI107945. Research Article The effects of anemia upon the ventilatory responses to transient and steady-state hypoxia were studied in unanesthetized goats. Responses to transient hypoxia (inhalation of several breaths of nitrogen) were considered to reflect peripheral chemoreceptor and non-chemoreceptor influences of hypoxia upon ventilatory control. In all goats, severe anemia (hemoglobin 3.1-4.8 g/100ml) markedly heightened the responses to transient hypoxia (from a mean of 0.27 to a mean of 0.75 liter/min/percent fall in SaO2). This phenomenon was substantially reversed by alpha-adrenergic blockade (phenoxybenzamine, 5 mg/kg). In contrast, the ventilatory responses to steady-state hypoxia were unaffected by severe anemia. These data suggest that severe anemia enhances the peripheral chemoreceptor-mediated response to hypoxia through a mechanism involving the alpha-adrenergic system. It also appears that a ventilatory depressant effect of hypoxia which is not mediated by the peripheral chemoreceptors is also enhanced by severe anemia, thereby preventing an increase in the steady-state ventilatory response to hypoxia. Finally, experiments involving variation in oxygen affinity of hemoglobin suggested that O2 tension rather than O2 availability in arterial blood is the major determinant of peripheral chemoreceptor activity. Find the latest version: https://jci.me/107945/pdf The Effect of Anemia on the Ventilatory Response to Transient and Steady-State Hypoxia TEODORO V. SANTIAGO, NORMAN H.