On certain peptides occurring in marine algae.

chrome c in solution is reduced very rapidly by a number of reducing agents, e.g. ascorbic acid which reduce the cytochrome c in the heart-muscle preparation much more slowly (Slater, 1949 b). Thus the various 'cytochrome reductases' which have been isolated may be the appropriate diaphorase, which when reduced, can be reoxidized either by methylene blue or cytochrome c in solution, but which in vivo is not oxidized by cytochrome c but by another catalyst, which may be a haematin compound like cytochrome c (Slater, 1949c).