Cytochrome Oxidase and Oxidation of Co in Eggs of the Sea Urchin Strongylocentrotus Purpuratus

Abstract

Black and Tyler (1959) have shown that developing eggs of the sea urchin and the gephyrean worm Urechis can oxidize CO, and these authors have presented data on the inhibitory effects of CO on respiration of developing embryos. The rates of CO-oxidation and ordinary respiration were such that in the presence of CO an excess gas-uptake occurred in the light in early developmental stages, but the percentage of excess uptake diminished as the respiratory rate increased. In the dark there was increasing inhibition of respiration and, in Urechis, diminishing CO-oxidation as the respiratory rate increased.The inhibitory effect of CO on cytochrome oxidase is well-known. Fenn and Cobb (1932) were the first to suggest that cytochrome oxidase could also oxidize this inhibitor, and Breckenridge (1953) obtained direct proof of this phenomenon, using labelled CO and purified cytochrome oxidase from pig heart. In the latter

The Respiratory Exchange of Diapausing Pupae of the Cecropia Silkworm in the Presence of Carbon Monoxide

“…In pupae whose metabolism has been enhanced by injury, the ratio is invariably less than 1, indicating that the rate of gas uptake is inhibited. (Breckenridge, 1953;Black and Tyler, 1959b). The most damaging evidence for this hypothesis is the augmentation of CO-combustion in light (Stannard, 1940;Black and Tyler, 1959a) where, presumably, the cytochrome oxidase-carbon monoxide complex is very unstable.…”