Identification of ubiquinone-50 as the major methylated nonpolar lipid in human monocytes. Regulation of its biosynthesis via methionine-dependent pathways and relationship to superoxide production.

摘要: Human blood monocytes incorporated the methyl group from methionine into their neutral lipids. The major methylated product was identified as ubiquinone-50 in monocytes, lymphocytes, and a variety of human tumor cell lines by several analytical procedures including TLC or high performance liquid chromatography ubiquinone-45 mouse line. Up to three groups were shown be derived mass spectrometry. rate synthesis assessed measuring labeled incorporation linear over 3-h period. Degradation ubiquinone proceeded slowly; 80% compound persisted after 18 h. dependence upon concentration established with an estimated apparent Km for about 20 microM. promoter, tetradecanoate phorbol acetate, potent stimulator superoxide anion (O2-) production phagocytic cells, inhibited at nanomolar concentrations but not under conditions where oxidation takes place. unaffected. Formylmethionylleucyl-phenylalanine, chemoattractant peptide which stimulates O2- also synthesis. degree inhibition either stimulus increased when medium low. These findings demonstrate that biosynthesis is regulable modulates both its inhibitory effects two stimuli production.