Oxidative phosphorylation in fractionated bacterial systems IV. Enzymic formation of reduced intermediates from vitamin K 1

Abstract

Two reduced intermediates of vitamin K 1 formed enzymically under anaerobic conditions by extracts of Mycobacterium phlei have been trapped by acetylation. The isolated acetyl derivative of one of the intermediates was identical to the diacetate of vitamin K 1 while the other was similar to synthetic naphthotocopherol (naphthochromanol) monoacetate. The unacetylated compounds which accumulate have similar absorption characteristics; however, they can be distinguished since on direct extraction of the enzymic reaction mixture with ether the naphthohydroquinone is spontaneously oxidized. Thus the naphthotocopherol-like compound can be measured and isolated in the absence of a trapping agent. The subcellular distribution and properties of the naphthoqiunone-chromanol-forming enzyme are described. The enzymically formed compound is reoxidized to vitamin K 1 with the release of inorganic phosphate. This intermediate may play a role in oxidative phosphorylation since it serves as an electron donor and ATP is formed.