Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MYOGLOBIN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1995

The role of H2O2-generated myoglobin radical in crosslinking of myosin.

The mechanism of myoglobin/H2O2 derived peroxidation of myosin was studied by comparing the catalytic activity of myoglobin and horseradish peroxidase using O-dianisidine, N-acetyl tyrosine and myosin as substrates. It was found that both hemoproteins induced myosin crosslinking and concomitant tyrosines oxidation to bityrosines, suggesting inter-molecular coupling of tyrosines in the crosslinking. The enzymatic activity of both hemoproteins on myosin was weak compared to small substrates. While horseradish peroxidase was much more active than myoglobin on small substrates, the reverse was true for myosin peroxidation. Since the suicidal interaction of myoglobin with H2O2 forms unstable tyrosine radicals, we suggest that the increased activity of myoglobin on myosin results from an efficient electron transfer between surface tyrosines of myosin and myoglobin but not horseradish peroxidase. These conclusions were supported by evidence that sperm whale myoglobin, which contains two active tyrosines--the heme-adjacent (tyrosine-103) and the surface (tyrosine-151), is more active as a mediator of myosin peroxidation than horse heart myoglobin which is devoid of the surface tyrosine.

Animals↗
PubMed1975

Decrease in oxygen affinity of myoglobin by formylation of vinyl groups of heme.

Three kinds of green synthetic myoglobin were prepared by recombination of horse heart apomyoglobin with spirographis (2-formyl-4-vinyl-), isospirographis (2-vinyl-4-formyl-), and 2,4-diformyldeuterohemins. The optical and oxygen binding properties of the reconstituted myoglobins containing two isomeric monoformyl-monovinylhemins were found to be different. The oxygen affinities (P50) of spirographis and 2,4-diformylmyoglobins are 2.7 and 2.8 mm Hg, respectively, at 25 degrees, and about 2.5 times lower than that of native protomyglobin, while that of isospirographis myoglobin is 1.0 mm Hg and is similar to native myoglobin. Spirographis oxymyoglobin has absorption maxima (alpha, beta, and Soret bands) at 601, 556.5, and 435 nm, isospirographis oxymyoglobin at 595, 550, 429 nm, and 2,4-diformyl oxymyoglobin at 603, 563.5, and 447 nm. The optical red shifts as well as the decrease in the oxygen affinities of these myoglobins are attributed mainly to the presence of strongly electron-attractive formyl side chains. Since the free isomers of monoformyl-monovinyl heme have similar properties, the differences observed after recombination with apoprotein must be caused by interactions with apomyoglobins. The degree of such a protein effect may be estimated by comparing the absorption spectra of heme before and after recombination and was found to differ among the various myoglobins. Comparison of the oxygen affinities of the myoglobins taking account of this protein factor showed that the increase in the P50 values are inversely related to that in the pK3 values of the free porphyrins. These results suggest the involvement of pi bonding in determining the oxygen-iron bond strength.

Animals↗
PubMed1975

Role of myoglobin in the oxygen supply to red skeletal muscle.

The contribution of nyoglobin to the oxygen uptake of red skeletal muscle was estimated from the difference in oxygen uptake with and without functional myoglobin. The oxygen uptake of bundles (25 mm long, 0.5 mm mean diameter) of muscle fibers teased from pigeon breast muscle was measured in families of steady states of oxygen pressure from 0 to 250 mm Hg. The oxygen-binding function of myoglobin, in situ in muscle fiber bundles, was abolished by treatment with nitrite of hydroxylamine, which convert oxymyoglobin in situ to high spin ferric myoglobin, or with phenylhydrazine, which converts oxymyoglobin to denatured products, or with 2-hydroxyethylhydrazine, which appears to remove myoglobin from the muslce. The oxygen uptake was again measured. At higher oxygen pressure, where oxygen availability does not limit the respiration of the fiber bundles, oxygen uptake is not affected by any of the four reagents, which is evidence that mitochondrial oxygen uptake is not impaired. At lower oxygen pressure, where oxygen uptake is one-half maximal, the steady state oxygen consumption is roughly halved by abolishing functional myoglobin. Under the steady state conditions studied, the storage function of myoglobin, being static, vanishes and the transport function stands revealed. We conclude from these experiments that myoglobin may transport a significant fraction of the oxygen consumed by muscle mitochondria.

Animals↗
PubMed1992

A novel site-directed mutant of myoglobin with an unusually high O2 affinity and low autooxidation rate.

Mutants of sperm whale myoglobin were constructed at position 29 (B10 in helix notation) to examine the effects of distal pocket size on the rates of ligand binding and autooxidation. Leu29 was replaced with Ala, Val, and Phe using the synthetic gene and Escherichia coli expression system of Springer and Sligar (Springer, B. A., and Sligar, S. G. (1987) Proc. Natl. Acad. Sci. U. S. A. 84, 8961-8965). Structures of the ferric forms of Val29 and Phe29, and the oxy form of Phe29 myoglobin were determined to 1.7 A by x-ray crystallography. The ferric mutant proteins are remarkably isomorphous with the wild type protein except in the immediate vicinity of residue 29. Thus, the protein structure in the distal pocket of myoglobin can accommodate either a large "hole" (i.e. Ala or Val) or a large side chain (i.e. Phe) at position 29 without perturbation of tertiary structure. Phe29 oxymyoglobin is also identical to the native oxy protein in terms of overall structure and interactions between the bound O2 and His64, Val68, Phe43, and Ile107. The distance between the nearest side chain atom of residue 29 and the second atom of the bound oxygen molecule is 3.2 A in the Phe29 protein and 4.9 A in native myoglobin. The equilibrium constants for O2 binding to Ala29, Val29, and Leu29 (native) myoglobin are the same, approximately 1.0 x 10(6) M-1 at 20 degrees C, whereas that for the Phe29 protein is markedly greater, 15 x 10(6) M-1. This increase in affinity is due primarily to a 10-fold decrease in the O2 dissociation rate constant for the Phe29 mutant and appears to be the result of stabilizing interactions between the negative portion of the bound O2 dipole and the partially positive edge of the phenyl ring. Increasing the size of residue 29 causes large decreases in the rate of autooxidation of myoglobin: k(ox) = 0.24, 0.23, 0.055, and 0.005 h-1 for Ala29, Val29, Leu29 (native), and Phe29 myoglobin, respectively, in air at 37 degrees C. Thus, the Leu29----Phe mutation produces a reduced protein that is remarkably stable and is expressed in E. coli as 100% MbO2. The selective pressure to conserve Leu29 at the B10 position probably represents a compromise between reducing the rate of autooxidation and maintaining a large enough O2 dissociation rate constant to allow rapid oxygen release during respiration.

Amino Acid Sequence↗
PubMed1991

[Non-invasive evaluation of coronary reperfusion using myoglobin: significance of quantitative and semi-quantitative latex agglutination methods].

We assessed the usefulness of myoglobin measured by latex agglutination methods as a parameter for successful reperfusion of the infarct-related artery. Plasma myoglobin levels were measured for 25 patients with acute myocardial infarction in whom thrombolysis and/or percutaneous transluminal coronary angioplasty (PTCA) were performed within 8 hours after the onset of symptoms. Blood samples were obtained before and 56 +/- 26 min (mean +/- SD) after commencing treatment. Plasma myoglobin levels were measured by quantitative and semi-quantitative latex agglutination methods, which required a procedure time of about 10 min. Coronary reperfusion was achieved by thrombolysis or PTCA in 22 cases (Group 1) but was not achieved by thrombolysis in 7 cases (Group 2). Before treatment (4.2 +/- 1.2 hours after the onset of symptoms), plasma myoglobin levels measured quantitatively and semi-quantitatively were 434 +/- 330 ng/ml and 4.6 +/- 4.2 fold, respectively. After treatment, the increased rate of myoglobin was significantly higher in Group 1 (8.4 +/- 7.5 and 9.2 +/- 7.1) than in Group 2 (1.8 +/- 0.5 and 1.7 +/- 0.5). Plasma myoglobin levels measured by quantitative and semi-quantitative latex agglutination methods showed a close correlation (r = 0.91, p < 0.01). In conclusion, measurement of plasma myoglobin levels by latex agglutination methods is a rapid and reliable way to confirm successful coronary reperfusion.

Aged↗
PubMed1990

The effects of amino acid substitution at position E7 (residue 64) on the kinetics of ligand binding to sperm whale myoglobin.

Association and dissociation rate constants were measured for O2, CO, and alkyl isocyanide binding to a set of genetically engineered sperm whale myoglobins with site-specific mutations at residue 64 (the E7 helical position). Native His was replaced by Gly, Val, Leu, Met, Phe, Gln, Arg, and Asp using the synthetic gene and expression system developed by Springer and Sligar (Springer, B. A., and Sligar, S. G. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 8961-8965). The His64----Gly substitution produced a sterically unhindered myoglobin that exhibited ligand binding parameters similar to those of chelated protoheme suspended in soap micelles. The order of the association rate constants for isocyanide binding to the mutant myoglobins was Gly64 (approximately 10(7) M-1 s-1) much greater than Val64 approximately Leu64 (approximately 10(6) M-1 s-1) greater than Met64 greater than Phe64 approximately His64 approximately Gln64 (10(5)-10(3) M-1 s-1) and indicates that the barrier to isocyanide entry into the distal pocket is primarily steric in nature. The bimolecular rates of methyl, ethyl, n-propyl, and n-butyl isocyanide binding to the His64----Arg and His64----Asp mutants were abnormally high (1-5 x 10(6) M-1 s-1), suggesting that Arg64 and Asp64 adopt conformations with the charged side chains pointing out toward the solvent creating a less hindered pathway for ligand binding. In contrast to the isocyanide data, the association rate constants for O2 and CO binding exhibited little dependence on the size of the E7 side chain. The values for all the mutants except His64----Gln approached or were larger than those for chelated model heme (i.e. approximately 1 x 10(8) M-1 s-1 for O2 and approximately 1 x 10(7) M-1 s-1 for CO), whereas the corresponding rate parameters for myoglobin containing either Gln64 or His64 were 5- to 10-fold smaller. This result suggests that a major kinetic barrier for O2 and CO binding to native myoglobin may involve disruption of polar interactions between His64 and water molecules found in the distal pocket of deoxymyoglobin. Finally, the rate and equilibrium parameters for O2 and CO binding to the His64----Gln, His64----Val, and His64----Leu mutants were compared to those reported previously for Asian elephant myoglobin (Gln-E7), Aplysia limacina myoglobin (Val-E7), and monomeric Hb II from Glycera dibranchiata (Leu-E7).

Amino Acids↗
PubMedDate not supplied

[Features of determining autoantibodies to human myoglobin using an immunoenzyme analysis method].

Various procedures of immunoenzyme assay (ELISA) were studied for evaluation of autoantibodies against human myoglobin. Antigenic properties of myoglobin were lost after immobilization on solid-phase carrier, hence noncompetitive type of the assay is unsuitable for these analyses. Exogenous myoglobin did not inhibit practically the blood serum immunoglobulins, which have reacted with immobilized myoglobin. These immunoglobulins appear to be autoantibodies against other antigens cross reacting with myoglobin. The procedure of competitive ELISA, involving solid phase immobilized specific antimyoglobin antibodies, was developed and assayed; an obligatory condition for the procedure developed is separation of immunoglobulins from myoglobin. Myoglobin and its naturally occurring antibodies were found as immunocomplexes in circulation.

Autoantibodies↗
PubMed1978

Acid and alkaline forms of the higher oxidation state of kangaroo, horse, and sperm whale myoglobin.

Myoglobin(IV), the derivative of myoglobin at the formal oxidation state IV, prepared from kangaroo (Megaleia rufa), horse, or sperm whale myoglobin, when cooled to liquid nitrogen temperature, assumes acid and alkaline forms with different optical spectra. The essential features of the optical spectra of the acid forms are the same as those of leghemoglobin(IV) and are very similar to those of optical spectra of the red higher oxidation states of catalases and peroxidases. This shows that the configuration of the heme iron is the same throughout these compounds. That configuration is believed to be Fe(IV) in a porphyrin environment. The optical spectra of alkaline mammalian myoglobin(IV), like that of alkaline leghemoglobin(IV), resemble those of the alkaline low spin ferric proteins. Kangaroo myoglobin(IV) may be prepared by reaction of ferrous myoglobin with hydrogen peroxide. The acid forms of myoglobin(IV) are conveniently prepared by cooling solutions in borate buffers, initially pH 8.3, to liquid nitrogen temperature. At this temperature borate buffers become acidic.

Animals↗
PubMed1988

Serum myoglobin levels in patients with ischemic myocardial insult.

Serum myoglobin levels were studied in 178 consecutive patients admitted for chest pain due to ischemic cardiac injury. Serum myoglobin level was compared with the clinical condition, electrocardiographic changes, and serum creatine kinase levels. Elevated serum myoglobin concentration was present in all patients with acute myocardial infarction, as defined by World Health Organization, Geneva, criteria, and, in addition, in about 50% of patients with so-called acute coronary insufficiency. On this basis we could define two different groups of patients with acute coronary insufficiency: cases exhibiting elevated serum myoglobin levels (group 1) and those with normal levels (group 2). In group 1 although creatine kinase levels were in the normal range, they were significantly higher than in group 2. Four patients from group 1 developed heart failure and another a typical acute myocardial infarction during hospitalization, whereas no patients of group 2 had such complications. In patients with acute myocardial infarction, the elevation of serum myoglobin preceded that of creatine kinase in most cases. Myoglobin release appears to be related to infarct size, the highest levels were found in extensive myocardial infarction and less marked elevations in cases of subendocardial infarction and in half of the cases with acute coronary insufficiency. It is proposed that serum myoglobin is a reliable measure of myocardial necrosis and serves to detect a hitherto undefined population of small-size acute myocardial infarction, with its attendant clinical and prognostic implications.

Coronary Disease↗
PubMed1987

Serum myoglobin in patients on intermittent and continuous ambulatory peritoneal dialysis.

Serum myoglobin levels were determined in patients maintained on chronic peritoneal dialysis. Eleven intermittent peritoneal dialysis patients had a mean serum myoglobin of 174 +/- 29 ng/ml. In 7 patients tested serially, there was no consistent change in serum myoglobin: the mean level was 154 +/- 36 ng/ml pre-dialysis and 170 +/- 20 ng/ml post-dialysis. Seventeen patients on continuous ambulatory peritoneal dialysis had a mean serum myoglobin of 215 +/- 18 ng/ml. Two patients given oral carnitine supplements had a substantial decrease in their serum myoglobin levels. Patients on peritoneal dialysis, like those on hemodialysis, tend to have elevated serum myoglobin levels, and neither form of dialysis affects serum myoglobin concentration. This hypermyoglobinemia may be due to metabolic changes in muscle.

Adult↗
PubMed1979

[Plasma myoglobin level as a course criterium in patients with acute myocardial infarct].

Myoglobin and the enzymatic activity of creatine phosphokinase CK), MB-isoenzyme of CK (CK-MB), aspartate aminotransferase (GOT), alanine aminotransferase (GPT) and lactic acid dehydrogenase (LDH) were serially determined in 10 patients with acute myocardial infarction. Additionally the same parameters were assessed in 5 patients with angina pectoris for 24 hours after bicycle ergometry. 10 in-patients served as controls. Myoglobin was determined by radioimmunoassay and the other enzyme activities according to the current kinetic methods. Comparison of myoglobin with the enzymatic parameters showed that the myoglobin peak occurs 5.6 hours after the beginning of the sampling period, i.e. 7.3 hours earlier than CK and CK-MB and 11.6 hours earlier than GOT. In analogy to this finding the descending limb of the myoglobin curve was significantly earlier at a level of one third of the peak value, i.e. 8.2 hours earlier than CK-MB, 18.8 hours earlier than CK and 27.3 hours earlier than GOT. No signs of myocardial necrosis in terms of myoglobin or enzymatic activity could be detected after bicycle ergometry. It is concluded that myoglobin is a more sensitive parameter for assessment of the acute phase in patients with myocardial infarction than the usualy enzymatic parameters.

Acute Disease↗
PubMed1980

Properties of monoclonal antibodies specific for determinants of a protein antigen, myoglobin.

Monoclonal hybridoma antibodies specific for the protein antigen sperm whale myoglobin were produced using hyperimmune spleen cells from mice with the genetic trait of high responsiveness to myoglobin. Antibodies from the several clones tested were found to produce linear Scatchard plots, as predicted for homogeneous antibodies, and to possess high affinities for the immunogen (KA congruent to 10(9) M-1). None of the monoclonal antibodies tested reacted with either fragment (1-55) or fragment (132-153) of sperm whale myoglobin. Competitive binding assays using human and horse myoglobins suggested that several of these monoclonal antibodies, which can readily distinguish these myoglobins, recognize different antigenic determinants on the myoglobin molecule. Studies using additional myoglobin sequence variants as competitors should be able to more closely define these antigenic determinants.

Animals↗
PubMed1983

Regional muscle tension and pain ("fibrositis"). Effect of massage on myoglobin in plasma.

In thirteen patients, all women, with regional muscle tension and pain ("fibrositis") plasma myoglobin concentration was measured before and after massage. A significant increase was observed in the plasma myoglobin concentration reaching a maximum three hours after the start of massage treatment (median 133 micrograms/l). A positive correlation was found between the degree of muscle tension and the increase in plasma myoglobin concentration. After repeated massage treatment a gradual decline could be demonstrated in the increase of the plasma myoglobin concentration in coincidence with the efficacy of the treatment. Opposed to this only normal levels of myoglobin were found in plasma when muscles without tenderness and pain were treated with massage. The observed increase of myoglobin in plasma after massage indicates a leak of myoglobin from the muscle fibres, which suggests that regional muscle tension and pain is associated with disorders in the muscle fibres.

Adult↗
PubMed1983

Usefulness of serial determinations of myoglobin and creatine kinase in serum compared for assessment of acute myocardial infarction.

Twenty-one patients with their first myocardial infarction underwent serial blood sampling every 2 h for determination of serum creatine kinase (CK) and myoglobin during the first 48-72 h after onset of pain. The first blood sample, obtained at a mean time of 4.4 h after infarct onset, invariably showed increased myoglobin (mean, 8.3-fold normal), whereas CK was often normal (mean, 1.6-fold normal). Peak myoglobin values occurred earlier than peak CK values (9.9 h vs 21.6 h, p less than 0.0005), but there was a significant correlation of peak values (myoglobin = 0.384CK - 0.264, r = 0.794, p less than 0.0005). The mean exponential disappearance rate (Kd) of CK was 0.00106 min-1 and of myoglobin was 0.00265 min-1 (p less than 0.0005). The disappearance of myoglobin was well described by a mono-exponential expression except in two patients. The total duration of the increase in myoglobin was significantly less than that of CK (34.7 h vs 74.4 h, p less than 0.0005).

Creatine Kinase↗
PubMed1982

The effect of renal failure and hemodialysis on serum and urine myoglobin.

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.

Adult↗
PubMed1996

Evaluation of myoglobin clearance during continuous hemofiltration in a swine model of acute renal failure.

Rhabdomyolysis is characterized by extensive damage of striated muscle, while the major complication of this disease is the development of acute myoglobinuric renal failure. Although first described more than five decades ago very little has changed with regard to the management of this entity as conventional hemodialysis has not been shown to effect myoglobin elimination. However, continuous arteriovenous hemofiltration (CAVH) offers an alternative to conventional hemodialysis as this procedure is more effective particularly for removing larger molecular weight substances such as myoglobin. We studied the effect of CAVH on myoglobin clearance in an animal model of acute myoglobinuric renal failure. Swine (n = 6) were given 4 grams of equine myoglobin intravenously and underwent the CAVH procedure for six hours each. Once the filtering process was initiated there was a rapid and sustained production of ultrafiltrate. The clearance of myoglobin via the hemofilter was 2.05 +/- 1.48 L/day. The amount of myoglobin excreted in the ultrafiltrate over the six hour filtering period was 410 +/- 234 mg which accounts for 10.27 +/- 5.85 percent of the administered dose. Based on these findings, it appears that the hemofiltration system is a viable option for the removal of myoglobin from the systemic circulation.

Acute Kidney Injury↗
PubMed1997

[The importance of myoglobin in the pathogenesis of leptospirosis].

Measurements were made of serum and urine myoglobin in 48 patients with leptospiral jaundice (LJ) and 56 patients with various acute infections. At the height of LJ blood myoglobin level reached 28.96 +/- 4.3 micrograms/l (normal concentration 0.315 +/- 0.002 microgram/l). Compared to acute pneumonia, acute viral hepatitis, tonsillitis, erysipelas, diphtheria, health values, the ratio of serum myoglobin to urine myoglobin in leptospirosis made up 45.25 against 5.4, 4.8, 6.8, 3.7, 1.8 and 1.3, respectively. A relationship was found between concentrations of myoglobin, bilirubin, creatinine in the blood and leptospirosis severity. Elevation of serum myoglobin as a manifestation of specific myositis is pathognomic for leptospirosis and contributes to the onset of acute renal failure and disturbance of bilirubin metabolism. Quantitation of blood myoglobin may be helpful as an additional test for leptospirosis severity.

Adolescent↗
PubMed1976

Studies on monotreme proteins. VII. Amino acid sequence of myoglobin from the platypus, Ornithoryhynchus anatinus.

Myoglobin isolated from skeletal muscle of the platypus contains 153 amino acid residues. The complete amino acid sequence has been determined following cleavage with cyanogen bromide and further digestion of the four fragments with trypsin, chymotrypsin, pepsin and thermolysin. Sequences of the purified peptides were determined by the dansyl-Edman procedure. The amino acid sequence showed 25 differences from human myoglobin and 24 from kangaroo myoglobin. Amino acid sequences in myoglobins are more conserved than sequences in the alpha- and beta-globin chains, and platypus myoglobin shows a similar number of variations in sequence to kangaroo myoglobin when compared with myoglobin of other species. The date of divergence of the platypus from other mammals was estimated at 102 +/- 31 million years, based on the number of amino acid differences between species and allowing for mutations during the evolutionary period. This estimate differs widely from the estimate given by similar treatment of the alpha- and beta-chain sequences and a constant rate of mutation of globin chains is not supported.

Amino Acid Sequence↗