scholarly journals A cytochrome c methyltransferase from Crithidia oncopelti.

1982 ◽  
Vol 201 (2) ◽  
pp. 329-338 ◽  
Author(s):  
J Valentine ◽  
G W Pettigrew
Keyword(s):  
Cytochrome C ◽  
Cell Extract ◽  
Lysine Methylation ◽  
Methyltransferase Activity ◽  
Proline Residue ◽  
Cytochromes C ◽  
Lysine Residues ◽  
Low Degrees ◽  
Horse Cytochrome

The mitochondrial cytochrome c-557 of Crithidia oncopelti contains two lysine residues and an N-terminal proline residue that are methylated in vivo by the methyl group of methionine. The purified cytochrome can act as a methyl acceptor for a methyltransferase activity in the cell extract that uses S-adenosylmethionine as methyl donor. Crithidia cytochrome c-557 is by far the best substrate for this methyltransferase of those tested, in spite of the fact that methylation sites are already almost fully occupied. The radioactive uptake of [14C]methyl groups from S-adenosylmethionine occurred only at a lysine residue (-8) and the N-terminal proline residue. This methyltransferase appears to differ from that of Neurospora and yeast [Durban, Nochumson, Kim, Paik & Chan (1978) J. Biol. Chem. 253, 1427-1435; DiMaria, Polastro, DeLange, Kim & Paik (1979) J. Biol. Chem. 254, 4645-4652] in that lysine-72 of horse cytochrome c is a poor acceptor. Also, the Crithidia methyltransferase appears to be stable to carry lysine methylation much further to completion than do the enzymes from yeast and Neurospora, which produce very low degrees of methylation in native cytochromes c.

scholarly journals The effect of complete or specific partial acetimidylation on the biological properties of cytochrome c and cytochrome c-T

1984 ◽  
Vol 217 (3) ◽  
pp. 595-599 ◽  
Author(s):  
C J A Wallace
Keyword(s):  
Structural Change ◽  
Cytochrome C ◽  
Oxygen Uptake ◽  
Redox Potential ◽  
Biological Properties ◽  
Amino Groups ◽  
Cytochromes C ◽  
Restricted Region ◽  
Horse Cytochrome

The biological consequences of acetimidylation of all 19 epsilon-amino groups of horse cytochrome c are a slight decrease in both the redox potential of the protein and its ability to stimulate oxygen uptake in the cytochrome c-depleted-mitochondria assay. Examination of a number of specific partially acetimidylated analogues and acetimidylated cytochromes c of other species has shown that the changes in biological properties, which are associated with a slight structural change as monitored by n.m.r. spectroscopy [Boswell, Moore, Williams, Harris, Wallace, Bocieck & Welti (1983) Biochem. J. 213, 679-686], appear to stem from modification of residues in a restricted region of the sequence. The failure of the redox potential of Saccharomyces cerevisae cytochrome c to be affected by acetimidylation suggests that it is lysine-53, absent from that species, that is the sensitive residue.

scholarly journals Ionization of tyrosine and lysine residues in native and modified horse cytochrome c

1983 ◽  
Vol 213 (3) ◽  
pp. 679-686 ◽  
Author(s):  
A P Boswell ◽  
G R Moore ◽  
R J P Williams ◽  
D E Harris ◽  
C J A Wallace ◽  
...  
Keyword(s):  
Protein Structure ◽  
Cytochrome C ◽  
Tyrosine Residue ◽  
Alkaline Ph ◽  
Pka Values ◽  
Tyrosine Residues ◽  
Lysine Residues ◽  
Higher Temperature ◽  
Modified Proteins ◽  
Horse Cytochrome

1H-n.m.r. and 13C-n.m.r. spectroscopy of horse cytochrome c and 1H-n.m.r. spectroscopy of the lysine-modified proteins N epsilon-acetimidyl-, N epsilon-amidino-, N epsilon-trifluoroacetyl- and N epsilon-maleyl-cytochrome c have shown that, although the lysine modifications do not greatly perturb the protein structure at pH7 and 27 degrees C, at higher temperature or at alkaline pH some parts of the structure are markedly perturbed. At pH7 and 27 degrees C the region of the protein about Ile-57 is affected in all the modified proteins, though not all to the same degree. N epsilon-Maleylation most seriously affects the protein structure, and the fully maleylated protein is readily unfolded. At 27 degrees C all four of the tyrosine residues of native horse cytochrome c have pKa values above 11, but in N epsilon-acetimidyl-cytochrome c the pKa of one tyrosine residue is 10.2.

scholarly journals The conformation of eukaryotic cytochrome c around residues 39, 57, 59 and 74

1983 ◽  
Vol 213 (3) ◽  
pp. 687-700 ◽  
Author(s):  
M N Robinson ◽  
A P Boswell ◽  
Z X Huang ◽  
C G S Eley ◽  
G R Moore
Keyword(s):  
Cytochrome C ◽  
Redox State ◽  
Conformational Flexibility ◽  
Candida Krusei ◽  
Crystallographic Structure ◽  
Conformational Heterogeneity ◽  
X Ray ◽  
Cytochromes C ◽  
Similar Cluster ◽  
Horse Cytochrome

1H-n.m.r. studies of horse, tuna, Candida krusei and Saccharomyces cerevisiae cytochromes c showed that each of the proteins contains a similar cluster of residues at the bottom of the protein that assists in shielding the haem from the solvent. The relative positions of the residues forming these clusters vary continuously with temperature, and they change with the change in protein redox state. This conformational heterogeneity is discussed with reference to the conformational flexibility of cytochrome c around residues 57, 59 and 74. Spectroscopic measurements of pKa values for Lys-55 (horse and tuna cytochromes c) and His-33 and His-39 (C. krusei and S. cerevisiae cytochromes c) are in excellent agreement with expectations based on chemical-modification studies of horse cytochrome c. [Bosshard & Zürrer (1980) J. Biol. Chem. 255, 6694-6699] and on the X-ray-crystallographic structure of tuna cytochrome c [Takano & Dickerson (1981) J. Mol. Biol. 153, 79-94, 95-115].

scholarly journals The amino acid sequence of Phaseolus aureus L. (mung-bean) cytochrome c

1970 ◽  
Vol 117 (1) ◽  
pp. 183-192 ◽  
Author(s):  
E. W. Thompson ◽  
M. V. Laycock ◽  
J. A. M. Ramshaw ◽  
D. Boulter
Keyword(s):  
Amino Acid ◽  
Cytochrome C ◽  
Amino Acid Sequence ◽  
Mung Bean ◽  
Wheat Germ ◽  
Amino Acid Residues ◽  
Phaseolus Aureus ◽  
Single Polypeptide Chain ◽  
Cytochromes C ◽  
Lysine Residues

The amino acid sequence of Phaseolus aureus L. (mung-bean) cytochrome c has been determined. The molecule consists of a single polypeptide chain of 111 amino acid residues and is homologous with other mitochondrial cytochromes c. Comparison with the amino acid sequence of wheat-germ cytochrome c (Stevens, Glazer & Smith, 1967) shows 14 differences. On alignment with mammalian cytochromes c, mung-bean cytochrome c has an N-acetylated ‘tail’ of eight amino acid residues similar to that found in wheat-germ cytochrome c. Of the 22 positions in wheat-germ cytochrome c that contain amino acid residues unique to these positions, 20 were found to contain the same ones in mung-bean cytochrome c. The ∈-N-trimethyl-lysine residues reported for wheat-germ cytochrome c (Delange, Glazer & Smith, 1969) in positions 72 and 86 were also found in these positions in mung-bean cytochrome c. The sequence was determined from 3μmol, by using chymotryptic and tryptic peptides which were analysed by the ‘dansyl’–Edman method (Gray & Hartley, 1963a), with confirmation by amino acid analysis.

scholarly journals Electron transfer from Phanerochaete chrysosporium cellobiose oxidase to equine cytochrome c and Pseudomonas aeruginosa cytochrome c-551

1994 ◽  
Vol 298 (2) ◽  
pp. 329-334 ◽  
Author(s):  
M S Rogers ◽  
G D Jones ◽  
G Antonini ◽  
M T Wilson ◽  
M Brunori
Keyword(s):  
Electron Transfer ◽  
Cytochrome C ◽  
Cytochrome B ◽  
Gel Chromatography ◽  
Cytochromes C ◽  
Cellulose Breakdown ◽  
Value Decomposition ◽  
Rate Limit ◽  
Positively Charged

The electron-transfer reactions of cellobiose oxidase (CBO) have been investigated by conventional and by rapid-scan stopped-flow spectroscopy at pH 6.0. Analysis of the absorbance/time/wavelength matrix by Singular Value Decomposition (SVD) confirms earlier studies showing that cellobiose rapidly reduces the flavin group (7.7 s-1; cellobiose, 100 microM) which in turn slowly (0.2 s-1) reduces the cytochrome b moiety. In the presence of CBO, cellobiose reduces cytochromes c in a reaction that does not depend on oxygen or superoxide. The rate limit for this process is independent of the source of the cytochromes c and is identical with the rate of cytochrome b reduction. Rapid-mixing experiments show that cytochrome b may donate electrons very rapidly to either mammalian cytochrome c or bacterial cytochrome c-551. The reactions were second-order (kc = 1.75 x 10(7) M-1 x s-1; kc-551 = 4.3 x 10(6) M-1 x s-1; pH 6.0, 21 degrees C and I0.064) and strongly ionic-strength (I)-dependent: kc decreasing with I and kc-551 increasing with I. These results suggest the electron-transfer site near cytochrome b bears a significant negative charge. Equilibrium gel chromatography confirms that CBO oxidase and positively charged mammalian cytochrome c make stable complexes. These results are discussed in terms of a model suggesting an electron-transfer role for cytochrome b in vivo, possibly connected with radical-mediated cellulose breakdown.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

Role of Methylglyoxal in Diabetic Cardiovascular and Kidney Diseases: Insights from Basic Science for Application into Clinical Practice

2018 ◽  
Vol 24 (26) ◽  
pp. 3072-3083 ◽  
Author(s):  
Sowndramalingam Sankaralingam ◽  
Angham Ibrahim ◽  
MD Mizanur Rahman ◽  
Ali H. Eid ◽  
Shankar Munusamy
Keyword(s):  
Therapeutic Strategy ◽  
Kidney Diseases ◽  
Vascular Dysfunction ◽  
Dicarbonyl Compound ◽  
Renal Complications ◽  
Lysine Residues ◽  
Patients With Diabetes ◽  
Prevalence Of Diabetes Mellitus

Background: The incidence and prevalence of diabetes mellitus are increasing globally at alarming rates. Cardiovascular and renal complications are the major cause of morbidity and mortality in patients with diabetes. Methylglyoxal (MG) - a highly reactive dicarbonyl compound – is increased in patients with diabetes and has been implicated to play a detrimental role in the etiology of cardiovascular and renal complications. Derived from glucose, MG binds to arginine and lysine residues in proteins, and the resultant end products serve as surrogate markers of MG generation in vivo. Under normal conditions, MG is detoxified by the enzyme glyoxalase 1 (Glo1), using reduced glutathione as a co-factor. Elevated levels of MG is known to cause endothelial and vascular dysfunction, oxidative stress and atherosclerosis; all of which are risk factors for cardiovascular diseases. Moreover, MG has also been shown to cause pathologic structural alterations and impair kidney function. Conversely, MG scavengers (such as N-acetylcysteine, aminoguanidine or metformin) or Nrf2/Glo1 activators (such as trans-resveratrol / hesperetin) are shown to be useful in preventing MG-induced cardiovascular and renal complications in diabetes. However, clinical evidence supporting the MG lowering properties of these agents are limited and hence, need further investigation. Conclusion: Reducing MG levels directly using scavengers or indirectly via activation of Nrf2/Glo1 may serve as a novel and potent therapeutic strategy to counter the deleterious effects of MG in diabetic complications.

scholarly journals Cytochrome c Deficiency Differentially Affects the In Vivo Mitochondrial Electron Partitioning and Primary Metabolism Depending on the Photoperiod

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 444
Author(s):  
Igor Florez-Sarasa ◽  
Elina Welchen ◽  
Sofia Racca ◽  
Daniel H. Gonzalez ◽  
José G. Vallarino ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Tca Cycle ◽  
Day Length ◽  
Primary Metabolism ◽  
Stress Signaling ◽  
Alternative Pathways ◽  
Tca Cycle Intermediates ◽  
Growth Adaptation ◽  
Plant Respiration

Plant respiration provides metabolic flexibility under changing environmental conditions by modulating the activity of the nonphosphorylating alternative pathways from the mitochondrial electron transport chain, which bypass the main energy-producing components of the cytochrome oxidase pathway (COP). While adjustments in leaf primary metabolism induced by changes in day length are well studied, possible differences in the in vivo contribution of the COP and the alternative oxidase pathway (AOP) between different photoperiods remain unknown. In our study, in vivo electron partitioning between AOP and COP and expression analysis of respiratory components, photosynthesis, and the levels of primary metabolites were studied in leaves of wild-type (WT) plants and cytochrome c (CYTc) mutants, with reduced levels of COP components, under short- and long-day photoperiods. Our results clearly show that differences in AOP and COP in vivo activities between WT and cytc mutants depend on the photoperiod likely due to energy and stress signaling constraints. Parallel responses observed between in vivo respiratory activities, TCA cycle intermediates, amino acids, and stress signaling metabolites indicate the coordination of different pathways of primary metabolism to support growth adaptation under different photoperiods.

scholarly journals Comparison of yeast and beef cytochrome c oxidases. Kinetics and binding of horse, fungal, and Euglena cytochromes c.

1979 ◽  
Vol 254 (23) ◽  
pp. 11973-11981 ◽  
Author(s):  
J.K. Dethmers ◽  
S. Ferguson-Miller ◽  
E. Margoliash
Keyword(s):  
Cytochrome C ◽  
Cytochromes C
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