Horse cytochrome

A high-speed separation of tryptic peptides of horse cytochrome c is shown in Figure 6. As the temperature and flow rate were increased, the separation substantially improved, an observation consistent with data demonstrating that conformational issues may be increasingly important factors in peak broadening as the time scale of the chromatography approaches that... 

Figure 6 High-speed tryptic fingerprint. Horse cytochrome c was digested with trypsin and the peptide chromatographed in acetonitrile water 0.1% TFA at various temperatures and flow rates on a 15 x 0.2-cm PS-DVB column packed with 3-p, 300-A particles, (a) 26°C and 0.5 ml/min. (b) 42°C and 0.7 ml/min. (c) 70°C and 1.1 ml/min. Detection at 220 nm. Note that the resolution rises with the speed of separation.89 (From Swadesh, ]., BioTechniques, 9, 626, 1990. With permission.)...

The kinetics of the reactions of horse cytochrome c(II), M, 12,400, (charge 8+) reduction potential 260 mV, with parsley and French bean plastocyanins PCu(II) (charges — 7 and — 8 respectively), have been studied. As in the case of HIPIP, cytochrome c is not a physiologically relevant protein. It is nevertheless important in assessing different approaches prior to investigating the reactions of physiological redox partners. In the case of the reaction of parsley PCu(II) with cytochrome c(II), the rate constant (25 °C) is 1.5 X 10 s at pH7.6, 1 = 0.10 M(NaCl) [141]. There is no evidence... 

Figure 7.34 Two horse cytochrome c molecules, (PDB ILCl, in various colors as described in the text, and PDB IGIW in green). Visualized using The PyMOL Molecular Graphics System and ChemDraw Ultra, version 10.0. (Printed with permission of Delano Scientific, LLC and CambridgeSoft, Corporation.) (See color plate)...

Figure 16.20—Multiply charged molecular ions. An electrospray spectrum of horse cytochrome c, a protein of molecular weight 12360 Da is shown. Between two consecutive peaks in the molecular ion cluster, the charge state varies by one unit. The second spectrum corresponds to a high-resolution spectrum in the 772-774 m/z range. In this isotopic cluster, all ions carry the same number of charges. It is possible from either of these spectra to calculate the approximate molecular weight and the number of charges carried by the ions (spectra reprinted with permission from F. W. McLafferty et al.. Anal. Chem., 1995, 67, 3802-5. Copright 1995 American Chemical Society).

The decay curves of the triplet excited state of zinc porphyrin for TZnCCP and the [TZnCCP/cyt c] complex with reduced horse cytochrome c heme are exponential with the same decay rate. Upon addition of horse cyt c with the oxidized heme to the solution of ZnCCP, the TZnCCP decay remains exponential but the decay rate increases until a 1 1 ratio is reached and then remains constant. The form of the dependence between the rate and the concentration of cyt c indicates that ZnCCP and the cyt c form a strong 1 1 complex. These results indicate electron tunneling at the distance of 25 A to be the reason for the enhancement of TZnCCP decay in the presence of cyt c. The rate of electron transfer from TZnCCP to the low-spin ferriheme within the [ZnCCP/horse cyt c] complex was found to be 17 3 s 1 at 293 K [70]. 

The rate of electron tunneling from TZnCCP to the ferriheme of the yeast cytochrome c was found to be roughly 10 times bigger than that observed in the case of the homologous horse cytochrome c. This difference demonstrates the fine degree of species specificity involved in biological electron transfer and must reflect subtle structural differences between horse and yeast cytochromes [70],... 

Figure 1. (a) X-ray crystal structure of horse-heart ferricytochrome c.8 All protein atoms are shown in the C.-P.-K. form, while the heme group is shown in the stick form. All Arg and Lys residues are colored blue, while Glu and Asp are colored in red, to contrast the destribution of the most ionizable side chains, (b) The X-ray crystal structure of horse heart ferricytochrome c in complex with horse cytochrome c peroxidase (cep).9 The peroxidase is shown as a molecular surface model, with blue regions depicting positive and red representing negative electrostatic potential. Note the cluster of negative potential on ccp that surrounds the contact interface. 

Three more recent results clearly establish the high mass range capabilities of the FTMS experiment. Spectra for bovine insulin (Figure 3), a mixture of bovine insulin and porcine insulin (Figure 4), and horse cytochrome-C (Figure 5) were obtained on sample sizes of 100 pmol, 100 pmol (equimolar), and 250 pmol, respectively, and with sample ionization... 

Fig. 14.36. Structure of horse cytochrome c obtained from the Brookhaven Protein Data Bank. Shown is the conventional front face view highlighting the exposed edge of the heme group (dark gray) located in a region of positive surface charge resulting from several lysine residues. (Reprinted from E. Bowden, Wiring Mother Nature, Interface 6(4) 40—45, Fig. 1, 1997. Reproduced by permission of the Electrochemical Society, Inc.)...

FIGURE 8 Displacement histogram and UV detector trace for a selective displacement process. (A) Displacement separation of a three-component protein mixture using streptomycin sulfate A as a displacer. Column 100 X 5 mm i.d. strong cation exchange (8 m) carrier 30 mM sodium phosphate buffer, pH 6.0 feed 1.6 mL of 0.392 mAI ribonudease A, 0.42 mM horse cytochrome c and 0.34 mM lysozyme in the carrier. Total column loading 12.7 mg/mL column displacer 25 mM streptomycin sulfate A flow rate 0.2 mL/min fraction size 200 /iL. (Kundu et al.43) (B) UV detector trace monitored at 280 nm for the displacement separation shown below. 

PROP Reduced form crystallizes as separate needles oxidized form as rosettes. Mol wt about 13,000. Cytochrome c2 Needles changing to squares. Mol wt about 13,000. Cytochrome c3 Needles. Mol wt 11,300. SYNS CROMOCI CYTOREST FERRICYTO-CHROME C FERROCYTOCHROME C HEMATIN-PROTEIN HORSE-CYTOCHROME C HORSE HEART CYTOCHROME C LANDRAX MYOHEMA-TIN NITROSYLFERRICYTOCHROME C... 

Acetylation was performed using a modification of the method of Fraenkel-Cbnrat (9). Horse cytochrome-C (Sigma) was dissolved in 1(X) mM Tris pH 8.0 to give a concentration of 0.25 m ml. To approximately 2 nMoles of protein (1(X) pj)... 

Figure 1 Ribbon representations of the models for the solution structure of oxidized (left) and reduced (right) horse cytochrome c. Drawn with the program Molscript (29).

Reduction of horse cytochrome C with [Colsepll ", [Co(diAMsar)]2+, and [Co(NOcapten)]2+ cations was reported in Refs. 316-320. The intrinsic reactivity of these complexes with proteins make it possible the use of clathrochelates as potential protein redox titrants, electrochemical mediators, and electrode modifiers. 

Angiotensin-I, methionine enkephalin, substance-P, bovine trypsin, horse cytochrome-C, horse myoglobin, bovine insulin and egg-white lysozyme were purchased from Sigma Chemical Co. (St. Louis, MO) and used without further purification. 

Figure 16.12 Comparison of the experimental (symbols) overloaded elution band profiles of a mixture of is -chjnnotrypsinogen and horse-cytochrom c on a monolithic column of ion- exchange resin and calculated profiles. Top mobile phase 50 mM buffer, pH = 6.0 Bottom same mobile phase + 80 mM Na+. Left calculations made with the RD model. Right calculations made with the TD model. Reproduced with permission from S. Chose, S. M. Cramer,. Chromatogr. 928 (2001) 13 (Figures 5 and 6).

Fig. 26. Schematic representation of the internal hydrogen bond network in horse cytochrome Amino acid residues are indicated by single letter representation in...

In retrospect, it is recognized by the detailed analyses that when horse ferricytochrome c is used as the electron acceptor, nitrite of approximately one fourth as much as horse cytochrome c reduced is usually formed in the oxidation of hydroxylamine catalyzed by hydroxylamine oxidoreductase regardless of the amount of the ferricytochrome c added, if the reactions are performed in 0.1 M phosphate buffer, pH 8.0. As the rate of the reaction (3.4) is not so much slower than that of the reaction (3.3) as assumed previously, the reaction (3.4) seems to occur at a comparable rate to the reaction (3.3). 

---