Cytochrome oxidase from an extreme thermophile. Thermus thermophilus HB8

The cytochrome oxidase (EC 1.9.3.1) of $\text{Thermus}\text{thermophilus}$ HB8 was isolated from the membrane fraction, and was highly purified. The oxidase contained heme $\text{a}$ and heme $\text{c}$ as the prosthetic groups. The purified preparation showed a single band in polyacrylamide gel electrophoresis, and three major polypeptides with apparent molecular weights of 52,000, 37,000 and 29,000 were observed in the presence of sodium dodecyl sulfate. The enzyme reacted rapidly with $\text{T}\text{.}\text{thermophilus}$ cytochrome c-552. The oxidation of $\text{T}\text{.}\text{thermophilus}$ cytochrome $\text{c}$-555,549 by the enzyme was very slow, and was stimulated by the addition of cytochrome $\text{c}$-552. The enzyme was highly stable to heat.