Isolierung von Cytochrom P‐450 und des entsprechenden Reductasesystems aus Acinetobacter calcoaceticus

Abstract

AbstractCytochrome P–450 is found in soluble as well as in particulate fractions of n‐alkane‐induced cells of Acinetobacter calcoaceticus EB 104 as shown by differential centrifugation and; gelfiltration experiments. It is reduced by NADH in the presence of at least two soluble proteins. Particulate cytochrome P–450 was extracted by Triton X‐100 and purified to homogeneity. The 80 fold enrichment resulted in a content of 19.0 nmol cytochrome P‐450/mg protein. The maxima of the absolute spectra are 417 nm for the oxidized, 408 nm for the reduced and 448 nm for the CO complex of reduced cytochrome. A ferredoxin, identified by maxima of 415 and 460 nm in the absorption spectrum of the oxidized form and by the occurrence of acid‐labile sulfur, as well as a corresponding NADH‐dependent ferredoxin reductase were isolated independently from the same bacterial strain. Enzymatic reduction of purified cytochrome P–450 is mediated by these proteins, which are discussed as in vivo components of the cytochrome P–450 system of A. calcoaceticus EB 104.