levels of cytochrome c in mitochondria, giving a low a + as/c ratio, and (b) low contents of cytochromes ¿>5 and P-450 in microsomes. Analysis in whole homogenates of hepatomas showed more pronounced decrease of the amount of cytochrome a + a3, presumably due to the decrease of the number of mitochondria in hepatoma cells. The livers of the tumor-bearing rats are also characterized by the simi...

The amino acid sequences of cytochromes c from many species have been shown to be homologous, the number of residues which differ depending on the biological relationship of the species being compared (2, 3). At the time the present study of dog heart cytochrome c was undertaken, only t’hc sequences of horse (4) and human (5) cytochromes c were known. It was essential, therefore, to determine t...

Heme attachment to c-type cytochromes in bacteria requires cysteine thiols in the CXXCH motif of the protein. The involvement of the periplasmic disulfide generation system in this process remains unclear. We undertake a systematic evaluation of the role of DsbA and DsbD in cytochrome c biogenesis in Escherichia coli and show unequivocally that DsbA is not essential for holocytochrome productio...

The cytochrome P450 monooxygenases are an important metabolic system whose level of activity can be influenced by several dietary constituents. We examined the effects of six known P450 inducers on the levels of total cytochromes P450, cytochrome b(5), and six monooxygenase activities in adult German cockroaches. In addition, the levels of CYP6L1 and CYP9E2 mRNA were also investigated. Phenobar...

Highly purified cytochrome c1, which consists of only one heme peptide and does not form a stable c1-c complex (c1-H-c complex), was used in studies of electron transfer between cytochrome c1 and c. Results show that a stable and ionic-strength-sensitive c1-c complex (i.e., the c1-H-c complex) in the forms of the various oxidation states is not required, in contrast to the current belief of the...

In the present study we describe the complete cytochrome P450 complement, the "CYPome," of Streptomyces coelicolor A3(2). Eighteen cytochromes P450 (CYP) are described, in contrast to the absence of CYPs in Escherichia coli, and the twenty observed in Mycobacterium tuberculosis. Here we confirm protein identity as cytochromes P450 by heterologous expression in E. coli and measurement of reduced...