Showing papers on "Myoglobin published in 1982"
TL;DR: On exposure to oxygen, the purple ferrous haem pigment, myoglobin, forms the bright red covalent complex, oxymyoglobin this paper, which is the unattractive brown pigment, is affected principally by reducing capacity of the muscle, oxygen availability and temperature.
307 citations
TL;DR: The most significant factor affecting colour stability of beef muscles appears to be their enzymic activity which determines the rate of myoglobin oxidation.
284 citations
TL;DR: Several hemoglobins and bovine myoglobin are shown to undergo autooxidation reactions promoted by anions, which can not be fully accommodated by mechanisms in which the Met species forms either via dissociative loss of superoxide from the oxy species followed by anion binding or via displacement of protonated dioxygen from oxyheme upon nucleophilic attack of the anion at heme iron.
236 citations
165 citations
TL;DR: The denaturation of ribonuclease A, lysozyme alpha-lactalbumin, and myoglobin by urea, Guanidine hydrochloride, and guanidine thiocyanate has been followed with the use of difference spectral measurements and the free energy of stabilization (delta GH2OD) has been determined.
162 citations
TL;DR: Nuclear magnetic resonance studies of 129Xe are consistent with one kinetically distinguishable binding environment in methemoglobin and two in metmyoglobin, and one of the binding sites has similar NMR and kinetic properties of those for meethemoglobin.
Abstract: Nuclear magnetic resonance studies of 129Xe are consistent with one kinetically distinguishable binding environment in methemoglobin and two in metmyoglobin. The Xe binding site in methemoglobin is assigned to a cavity formed by the A-B and G-H corners of the globin chain [Schoenborn, B.P. (1965) Nature (London) 208, 760-762]. The small differences between alpha-hemoglobin and beta-hemoglobin are not resolved by the NMR experiments. The Xe association rate constant at 18 degrees C with methemoglobin is greater than 6 X 10(7) M-1 s-1 with an activation barrier of approximately 13 kcal/mol. One of the binding sites in metmyoglobin associated with a cavity on the proximal side of the porphyrin ring, opposite the O2 binding site [Schoenborn, B.P., Watson, H.C., & Kendrew, J.C. (1965) Nature (London) 207, 28-30]. An estimate of the association rate constant of Xe at 18 degrees C is 1 X 10(7) M-1 s-1 with an activation barrier of approximately 16 kcal/mol. The second metmyoglobin binding site has similar NMR and kinetic properties of those for methemoglobin.
142 citations
TL;DR: In this article, the recombination after flash photolysis of dioxygen and carbon monoxide with sperm whale myoglobin (Mb), and separated beta chains of human hemoglobin (beta A) and hemoglobin Zurich (beta ZH), has been studied as a function of pH and temperature from 300 to 60 K.
Abstract: The recombination after flash photolysis of dioxygen and carbon monoxide with sperm whale myoglobin (Mb), and separated beta chains of human hemoglobin (beta A) and hemoglobin Zurich (beta ZH), has been studied as a function of pH and temperature from 300 to 60 K. At physiological temperatures, a preequilibrium is established between the ligand molecules in the solvent and in the heme pocket. The ligand in the pocket binds to the heme iron by overcoming a barrier at the heme. The association rate is controlled by this final binding step. The association rate of CO to Mb and beta A is modulated by a single titratable group with a pK at 300 K of 5.7. The binding of CO to beta ZH, in which the distal histidine is replaced by arginine, does not depend on pH. Oxygen recombination is independent of pH in all three proteins. Comparison of the binding of CO at 300 K and at low temperatures shows that pH does not affect the preequilibrium but changes the barrier height at the heme. The pH dependence and the difference between O2 and CO binding can be explained by a charge-dipole interaction between the distal histidine and CO.
138 citations
TL;DR: The dissimilarities observed between P-450 and myoglobin in their reactivity toward sulfur donor ligands at least partly reflect the variation in heme iron electron density resulting from their different endogenous axial ligands and may, in turn, help to explain their respective physiological functions of oxygen activation and reversible oxygen binding.
131 citations
110 citations
TL;DR: Findings provide strong support for the presence of four conformers of significantly different structure at the heme ligand-binding site and for rapid interconversions among these structures.
104 citations
TL;DR: Under all the conditions explored, the binding constants for the reaction of ferric sperm whale and Aplysia myoglobins with imidazole are very similar when measured in solution and in single crystals, thus indicating that the crystalline lattice does not exert large strains on the structure of the active site.
TL;DR: Among RMS, staining correlated directly with cytoplasmic differentiation regardless of histologic type, and should be considered an extremely sensitive and specific tissue tumor marker for rhabdomyosarcoma of considerable clinical importance.
Abstract: Myoglobin, found exclusively in striated muscle, can be considered a fetal antigen. This study investigated its usefulness as a tumor marker for rhabdomyosarcoma (RMS) using an immunoperoxidase technique. Eight-nine percent (89%) or 27 rhabdomyosarcomas contained immunoreactive myoglobin. In contrast, all other soft tissue tumors (54), carcinomas (10), and numerous normal tissues including smooth muscle were negative. Among RMS, staining correlated directly with cytoplasmic differentiation regardless of histologic type. Importantly, six of nine small cell RMS with no initially appreciated cytoplasm were positive, although focally. Since the three negative RMS had only limited tissue available for study, it remains possible that all RMS would exhibit rare positivity if sizeable specimens were tested. Myoglobin should be considered an extremely sensitive and specific tissue tumor marker for rhabdomyosarcoma of considerable clinical importance.
TL;DR: R resonance Raman spectra of the oxy forms of cobalt–porphyrin-substituted myoglobin and haemoglobin recorded in buffered H2O and D2O solutions indicate that the bound oxygen in oxyCoMb and in both subunits of oxyCoHb interacts with the adjacent exchangeable proton, and confirms the formation of a hydrogen bond between the boundoxy and the distal histidine.
Abstract: The origin of the differences in oxygen binding energy in various haemoglobins and myoglobins has long been debated. Perutz1 proposed that the haem-coordinated histidine (proximal histidine) strains the haem iron in low affinity globins but relaxes it in high affinity globins. The existence of such tension in T-structure deoxyhaemoglobin (deoxyHb) was recently confirmed by electron paramagnetic resonance (EPR)2,3, resonance Raman4,5 and NMR6 spectroscopy. Although its contribution to the free energy of cooperativity is insignificant in the deoxy state, the tension at the haem is considered to be ∼1 kcal mol−1 for the ligated form in which the haem iron moves into the porphyrin plane7. The remaining free energy is probably stored in other parts of the molecule. Therefore, a study of the stabilization mechanisms of the oxygenated form became increasingly important. A hydrogen bond between the bound oxygen and the distal histidine has been proposed by Pauling8; this would be expected to stabilize the oxy form of the protein and could contribute to the regulation of the oxygen affinity through the oxygen dissociation rate. A series of EPR and functional studies on various cobalt-substituted monomeric haemoglobins and myoglobins suggested the presence of such hydrogen bonding8–12 and it has recently been established in crystals of oxy iron myoglobin (oxyFeMb)13 and in oxyhaemoglobin14. Here we present resonance Raman spectra of the oxy forms of cobalt–porphyrin-substituted myoglobin and haemoglobin (CoMb and CoHb) recorded in buffered H2O and D2O solutions at 406.7 nm excitation. Only the Raman lines corresponding to the O—O stretching mode of the bound oxygen15, appearing near 1,130 cm−1, are shifted (2–5 cm−1) on replacement of H2O by D2O; no other vibrations, including the Co—O2 stretching mode, exhibit any frequency shifts. This indicates that the bound oxygen in oxyCoMb and in both subunits of oxyCoHb interacts with the adjacent exchangeable proton, and confirms the formation of a hydrogen bond between the bound oxygen and the distal histidine9.
TL;DR: It is concluded that functional intracellular myoglobin is important in maintaining oxygen consumption and tension generation in exercising skeletal muscle.
Abstract: Short-term perfusion of the isolated dog gastrocnemius-plantaris muscle with hydrogen peroxide resulted in a decrease in steady-state muscle oxygen consumption and isometric tension generation. Hydrogen peroxide converted intracellular myoglobin to products incapable of combination with oxygen, but had no deleterious effect on neuromuscular transmission or on mitochondrial oxidative phosphorylation. It is concluded that functional intracellular myoglobin is important in maintaining oxygen consumption and tension generation in exercising skeletal muscle.
TL;DR: With excitation at 406.7 nm, the resonance Raman enhancement of the bound v(N-O) stretch at approximately 1623 cm-1 in nitrosylhemoglobin A and nitroSylmyoglobin, indicating the existence of a charge-transfer transition underlying the strong Soret band.
Abstract: With excitation at 406.7 nm, we have observed the resonance Raman enhancement of the bound v(N-O) stretch at approximately 1623 cm-1 in nitrosylhemoglobin A and nitrosylmyoglobin, indicating the existence of a charge-transfer transition underlying the strong Soret band. The v(Fe-NO) stretch at 551 cm-1 has also been detected in the Soret as well as in the Q-band region, a phenomenon similar to the v(Fe-O2) and v(Fe-CO) stretches in oxy and carbon monoxy hemoproteins. It appears that these iron-ligand vibrations ay be resonance enhanced via porphyrin pi leads to pi transitions. Upon addition of inositol hexaphosphate at pH 6.0, the v(Fe-NO) stretch at 551 cm-1 and a low-frequency mode at 301 cm-1 exhibit an intensity decrease by approximately one-half. Contrary to the work of Stong et al. [Stong, J. D., Burke, J. M., Daly, P., Wright. P., & Spiro, T. G. (1980) J. Am. Chem. Soc. 102, 5815], who employed an excitation wavelength at 454.5 nm, we observed no intensity increase at 592 cm-1 attributable to the v(Fe-NO) stretch from the pentacoordinated NO-heme complex in the alpha subunits.
TL;DR: Two monoclonal antibodies directed against different sites of the human myoglobin molecule have been tested for their cross-reactivities against several myoglobins including seven from mammalian species, leading to a possible localization of two antigenic domains in humanMyoglobin.
TL;DR: It is concluded that myoglobin entering the vascular space is normally cleared rapidly by renal catabolism, and seven myoglobin concentration-time patterns during acute myocardial infarction directly reflect patterns of protein entry into the vascularspace after release from injured tissue.
Abstract: Rates and mechanisms of myoglobin removal from plasma were examined in closed-chest dogs, using disappearance patterns of immunoreactivity and radioactivity after i.v. canine myoglobin radiolabeled with 125I. Arterial immunoreactive myoglobin concentration decreased monoexponentially over a 2-decade range, with rate constants of disappearance averaging -0.080 +/- 0.014 min-1 (+/- SD) (corresponding to half-times of disappearance of 8.9 +/- 1.5 min). Renal arteriovenous difference in immunoreactive myoglobin concentration documented extraction of the parent molecule, with extraction ratios averaging 0.36 +/- 0.06. Renal venous specific activity increased a few minutes after myoglobin administration, consistent with discharge from the kidney of nonimmunoreactive radiolabeled peptides of the parent molecule. Arterial disappearance of 125I was subsequently delayed in relation to immunoreactive myoglobin. Urinary recoveries of immunoreactive parent molecule and radiolabeled constituents were limited, averaging 2.5 +/- 1.1% and 12 +/- 1.1% over a 6-hour period. Arterial rate, constants of disappearance of immunoreactive myoglobin decreased markedly with decreases in renal perfusion produced by obstruction of renal arterial inflow. We conclude that myoglobin entering the vascular space is normally cleared rapidly by renal catabolism. Seven myoglobin concentration-time patterns during acute myocardial infarction directly reflect patterns of protein entry into the vascular space after release from injured tissue.
TL;DR: It is found that a single region on the surface of different species of myoglobin appears to be immunodominant for T lymphocytes, even though the residues in that region vary sufficiently that the T cells immune to one myoglobin do not crossreact with other myoglobins bearing substitutions at that site.
Abstract: We find that a single region on the surface of different species of myoglobin appears to be immunodominant for T lymphocytes, even though the residues in that region vary sufficiently that the T cells immune to one myoglobin do not crossreact with other myoglobins bearing substitutions at that site. Immunization of B10.S mice with sperm whale myoglobin elicits T-lymphocyte populations capable of recognizing sperm whale myoglobin but not horse myoglobin, whereas the converse is true when these mice are immunized with horse myoglobin. Using a series of myoglobin variants, we tested the effect of changes in primary sequence on the T-lymphocyte proliferative response. We were able to divide the myoglobin variants into two groups, depending on whether they cross stimulate sperm whale immune or horse immune T lymphocytes. The patterns of cross stimulation of both populations of myoglobin immune T lymphocytes were explained by amino acid substitutions at position 109. However, because sperm whale and horse myoglobin differ at this residue (glutamate vs. aspartate, respectively), T lymphocytes immune to each myoglobin do not crossreact with the other myoglobin. Additional data suggest that this immunodominant epitope also includes other residues nearby on the surface of the native molecule. Mixing experiments showed that the specificity was that of T lymphocytes and not antigen-presenting cells. Monoclonal anti-I-A blocking studies showed that both myoglobins are presented in association with the same Ia antigen. Possible explanations for the apparent immunodominance of this antigenic epitope, consisting of residue 109 and nearby residues on the surface of both myoglobins, include a peculiar immunogenicity of the surface topography of this site of a preferred orientation of the molecule imposed by antigen-presenting cells when T cells first encounter the antigen. The latter explanation is related to but distinct from "determinant selection." T-cell recognition of conformation is discussed.
TL;DR: Results demonstrate the existence of a substantial intracellular O2 gradient in myocytes and indicate that myoglobin does not have a significant role in facilitation of O2 diffusion to mitochondria.
TL;DR: Low-intensity running is a sufficient stimulus to induce most of the total possible mitochondrial increase in the red fiber types, whereas extremely fast running speeds are needed to stimulate significant increases in white muscle mitochondria and the mitochondrial differences in skeletal muscle between intensity groups cannot account for the differences in performance.
Abstract: HARMS, SANDRA J., AND ROBERT C. HICKSON. SheZetaZ muscle mitochondria and myogLobin, endurance, and intensity of training. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 54(3): 798-802,1983.-Female rats were trained by treadmill running 40 min/day, 6 days/wk up to 11,22, or 44 m/min for 14 wk. Low-intensity exercise (11 m/min) increased the activities of the mitochondrial markers, citrate synthase and succinate dehydrogenase, by 50 and 58% in fast-twitch red vastus lateralis (FTR) muscles and by 32 and 15%, respectively, in slow-twitch red soleus (STR) muscles. Running up to fourfold faster did not significantly elevate the activities of these enzymes beyond those obtained after running at 11 m/min. In contrast, there was a small but direct trend of training intensity with citrate synthase activity in fast-twitch white vastus lateralis (FTW) muscles. Myoglobin concentration tended to increase as a linear function of training intensity in FTR muscles. In STR muscle, the concentration of myoglobin increased 15% in the 11 m/min group but was essentially the same as control values in the 22 and 44 m/min groups. The concentration of myoglobin was not changed with training intensity in FTW muscle. Exercise time to exhaustion increased in proportion to training intensity. We conclude that 1) low-intensity running [approx 50% maximal O2 uptake or less] is a sufficient stimulus to induce most of the total possible mitochondrial increase in the red fiber types, whereas extremely fast running speeds are needed to stimulate significant increases in white muscle mitochondria; and 2) the mitochondrial differences in skeletal muscle between intensity groups cannot account for the differences in performance.
TL;DR: The effect of myoglobin on oxygen consumption and ATP production by isolated rat skeletal muscle mitochondria was studied under steady-state conditions of oxygen supply and functional myoglobin present in the solution had no effect on the relation of mitochondrial respiration and ATPproduction to liquid-phase oxygen pressure.
Abstract: The effect of myoglobin on oxygen consumption and ATP production by isolated rat skeletal muscle mitochondria was studied under steady-state conditions of oxygen supply. A method is presented for the determination of steady-state oxygen consumption in the presence of oxygen-binding proteins. Oxygen consumed in suspensions of mitochondria was replenished continuously by transfer from a flowing gas phase. Liquid-phase oxygen pressure was measured with an oxygen electrode; the gas-phase oxygen concentration was held constant at a series of fixed values. Oxygen consumption was determined from the characteristic response time of the system and the difference in the steady-state gas- and liquid-phase oxygen concentrations. ATP production was determined from the generation of glucose 6-phosphate in the presence of hexokinase. During steady-state mitochondrial oxygen consumption, the oxygen pressure in the liquid phase is enhanced when myoglobin is present. Functional myoglobin present in the solution had no effect on the relation of mitochondrial respiration and ATP production to liquid-phase oxygen pressure. Myoglobin functions in this system to enhance the flux of oxygen into the myoglobin-containing phase. Myoglobin may function in a similar fashion in muscle by increasing oxygen flux into myocytes.
TL;DR: Superoxide free radicals produced by the autoxidation of hemoglobin to methemoglobin do not seem to be involved in the mechanism of hemoglobins and myoglobin-induced vasocontraction as the contraction cannot be blocked by superoxide dismutase or other agents known to react with superoxide-generated products.
Abstract: ✓ The dose responses of canine basilar arteries to human hemoglobin, rabbit hemoglobin, horse-heart myoglobin, and human methemoglobin and cyanomethemoglobin are compared in this paper. The in vitro arterial segments responded similarly to the hemoglobins and myoglobin when doses were based on the hemoglobin dimer rather than on the tetramer. Superoxide free radicals produced by the autoxidation of hemoglobin to methemoglobin do not seem to be involved in the mechanism of hemoglobin-induced vasocontraction, as the contraction cannot be blocked by superoxide dismutase or other agents known to react with superoxide-generated products. Nonspecific uptake of hemoglobin into the smooth-muscle cells by pinocytosis is also discounted.
TL;DR: Raman intensity measurements for the Fe-O2 stretching band of HbO2 (Hb = hemoglobin) have been used to construct an excitation profile, which shows that resonance enhancement occurs mainly via the B and Q transition; no contribution is detectable from an out-of-plane charge-transfer transition.
Abstract: Raman intensity measurements for the Fe-O2 stretching band of HbO2 (Hb = hemoglobin) have been used to construct an excitation profile, which shows that resonance enhancement occurs mainly via the B and Q transition; no contribution is detectable from an out-of-plane charge-transfer transition. Direct coupling of VFe-O2 to the porphyrin pi-pi* transitions is explained on the basis of competition between the pi* orbitals of porphyrin and O2 for Fe d pi electrons. The RR spectrum of MbNO (Mb = myoglobin) at pH 8.4 is due solely to six-coordinate heme--NO, but lowering the pH to 5.8 converts the RR spectrum to one characteristic of five-coordinate heme--NO, consistent with Fe-ImH (ImH = imidazole) dissociation via protonation. The Fe-NO stretching frequencies are at 553 and 596 cm-1 for the high- and low-pH forms, as expected, but the low-pH form shows an additional 15NO-sensitive band, at 573 cm-1, which is assigned to Fe-N-O bending in the five-coordinate complex. The RR spectrum of MbO2 shows a shoulder at approximately 270 cm-1, which shifts down by approximately 3 cm-1 upon 18O2 substitution, and is suggested to contain the Fe-ImH stretching mode. The weakness of VFe-ImH, relative to VFe-O2, is attributable to the lack of ImH involvement in the heme pi bonding.
TL;DR: Rayleigh scattering experiments on metmyoglobin crystals and freeze dried myoglobin which was exposed to air with different partial pressure of water vapor show dynamic behaviour in crystals and in crystals the dynamic behaviour is hindered by the crystal packing.
Abstract: This paper reports Rayleigh scattering experiments on metmyoglobin crystals and freeze dried myoglobin which was exposed to air with different parital pressure of water vapor. While dry myoglobin shows no fluctuations between conformational substates such "breathing modes" are rarely seen in water covered myoglobin. Larger amounts of water increase the average mean square displacements. In crystals the dynamic behaviour is hindered by the crystal packing. The results are analysed by a theory describing the motion within the molecule by a Langevin equation with restoring forces corresponding to a square well potential.
TL;DR: The potential role of myoglobin as a protective agent against myocardial hypoxia was tested by exploiting naturally occurring differences in heart myoglobin content between two species of fish.
TL;DR: In this paper, single crystals of oxyproto and oxymesocobalt myoglobin were examined by electron paramagnetic resonance spectroscopy at ambient and cryogenic temperatures in order to determine the principal values and eigenvectors of g tensors and the hyperfine coupling tensors.
TL;DR: In mammals, the major proportion of body iron is found as the iron porphyrin complexes, haemoglobin, myoglobin and a variety of haem-containing enzymes and many other iron proteins are found in the tissues, including metallo-flavoproteins and other enzymes in which iron is a cofactor.
Journal Article•
TL;DR: In 33 patients with chronic renal disease, the concentration of myoglobin in serum and urine was found to be significantly elevated over that of normal controls, and the association between chronic renal failure and high concentration of serum and urinary myoglobin was confirmed.
Abstract: In 33 patients with chronic renal disease, the concentration of myoglobin in serum and urine was found to be significantly elevated over that of normal controls. Hemodialysis had no statistically significant effect in lowering the serum myoglobin of patients with end stage renal disease. Similarly, no difference was found in serum myoglobin in blood entering and leaving the dialysis coil. Since myoglobin was not detectable in the dialyzate, these data illustrate that myoglobin is not appreciably dialyzable. The association between chronic renal failure and high concentration of serum and urine myoglobin was confirmed. These abnormally high levels of myoglobin in serum and urine do not necessarily lead to myoglobinuric renal failure.
TL;DR: Unlike mammalian myoglobins, Aplysia myoglobin contains a single histidine residue that most likely corresponds to the heme-binding proximal one, its oxygenated form is extremely unstable and its CD magnitude is about two-thirds that of sperm whale myoglobin.
TL;DR: A phylogenetic study of this monomeric heme-containing protein clearly reveals that it arose via a gene duplication of hemoglobin near the time of the duplication that gave rise to the alpha and beta genes.