抄録
1. A highly purified preparation of cyto-chrome b was obtained from beef heart muscle by cholate-extraction, isolation by precipitation, solubilization with proteinase, ammonium sulfate fractionation, gel filtration, and chromatography on DEAE-cellulose.
2. The absorption spectra of the purified cytochrome b were observed and the extinc-tion ratios of the maxima were calculated.
3. The heme content of the preparation was determined to be 47.0 μmoles/g. protein, and the minimum molecular weight was calculated to be 21, 300. The molar extinction coefficients were also calculated.
4. The reduced cytochrome b was auto-xidizable and could combine with carbon monoxide. Under anaerobic conditions, the purified cytochrome b was reduced by lactate in the presence of yeast L-lactate dehydro-genase and this reaction was markedly ac-celerated by the addition of a catalytic amount of redox-dye as a mediator.
5. The heme group of the purified cytochrome b was identified as protoheme.
The author wishes to thank Prof. K. Okunuki for his kind advice and Drs. I. Sekuzu and Y. Orii for their helpful discussion and suggestions during this work.
