Cytochrome System of Streptomycetes

Abstract

IT has recently been reported that the cytochrome System in the genus Streptomyces differs strikingly from that found in most aerobic cells¹. No α-type cytochrome could be seen in the 10 species examined, and in some cases cytochrome c was also apparently missing. The suggestion² that the respiratory chain may terminate with electron transfer from cytochrome b to oxygen was further supported by the partial purification of an autoxidizable cytochrome b. Since a similar ‘b-oxidase hypothesis’ has been invoked to account for the cyanide-resistant respiration in higher plants^3,4, the Streptomycetes were re-examined with the view of shedding some light on this problem. However, a survey of representative Streptomyces species showed that their respiration can be inhibited by cyanide and further studies have shown that a-, b-, and c-type cytochromes are present in all cases.