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 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 Appearance of Transient Species of Cytochrome c upon Rapid Oxidation or Reduction at Alkaline pH

1973 ◽  
Vol 248 (23) ◽  
pp. 8130-8136 ◽  
Author(s):  
David O. Lambeth ◽  
Kenneth L. Campbell ◽  
Robert Zand ◽  
Graham Palmer
Keyword(s):  
Cytochrome C ◽  
Alkaline Ph ◽  
Transient Species

scholarly journals Purification and properties of a cross-linked complex between cytochrome c and cytochrome c peroxidase

1982 ◽  
Vol 201 (1) ◽  
pp. 9-18 ◽  
Author(s):  
G W Pettigrew ◽  
S Seilman
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Peroxidase ◽  
Sodium Phosphate Buffer ◽  
Oxidation Reduction ◽  
Purification And Properties ◽  
Lysine Residues ◽  
The Cross ◽  
Nadh Cytochrome ◽  
Stable Association ◽  
Covalently Linked

Cytochrome c (horse heart) was covalently linked to yeast cytochrome c peroxidase by using the cleavable bifunctional reagent dithiobis-succinimidyl propionate in 5 mM-sodium phosphate buffer, pH 7.0. A cross-linked complex of molecular weight 48 000 was purified in approx. 10% yield from the reaction mixture, which contained 1 mol of cytochrome c and 1 mol of cytochrome c peroxidase/mol. Of the total 40 lysine residues, four to six were blocked by the cross-linking agent. Dithiobis-succinimidylpropionate can also cross-link cytochrome c to ovalbumin, but cytochrome c peroxidase is the preferred partner for cytochrome c in a mixture of the three proteins. The cytochrome c cross-linked to the peroxidase can be rapidly reduced by free cytochrome c-557 from Crithidia oncopelti, and the equilibrium obtained can be used to calculate a mid-point oxidation-reduction potential for the cross-linked cytochrome of 243 mV. Mitochondrial NADH-cytochrome c reductase will reduce the bound cytochrome only very slowly, but the rate of reduction by ascorbate at high ionic strength approaches that for free cytochrome c. Bound cytochrome c reduced by ascorbate can be re-oxidized within 10s by the associated peroxidase in the presence of equimolar H2O2. In the standard peroxidase assay the cross-linked complex shows 40% of the activity of the free peroxidase. Thus the intrinsic ability of each partner in the complex to take part in electron transfer is retained, but the stable association of the two proteins affects access of reductants.

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.

Analysis of the pH-dependent stability and millisecond folding kinetics of horse cytochrome c

2015 ◽  
Vol 585 ◽  
pp. 52-63 ◽  
Author(s):  
Rishu Jain ◽  
Rajesh Kumar ◽  
Sandeep Kumar ◽  
Ritika Chhabra ◽  
Mukesh Chand Agarwal ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Folding Kinetics ◽  
Ph Dependent ◽  
Kinetics Of ◽  
Horse Cytochrome
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