title: The activity and kinetic properties of mevalonate kinase in superovulated rat ovary.
abstract: Methods are described for the assay and partial purification of mevalonate kinase from superovulated rat ovary. The total activity of mevalonate kinase in superovulated rat ovary was 1.6+/-0.14units/g wet wt.; it was unchanged by the administration of luteinizing hormone in vivo. The K(m) of a partially purified preparation of mevalonate kinase for dl-Mevalonate was 3.6+/-0.5mum; its K(m) for MgATP(2-) was 120+/-7.7mum. The enzyme was inhibited by geranyl pyrophosphate and farnesyl pyrophosphate, but not by isopentenyl pyrophosphate or 3,3'-dimethylallyl pyrophosphate. dl-mevalonate 5-phosphate inhibited at high concentrations. With both geranyl pyrophosphate and farnesyl pyrophosphate the inhibition was competitive with respect to MgATP(2-). The K(i) for inhibition by geranyl pyrophosphate was 1.3+/-0.2mum; the K(i) for inhibition by farnesyl pyrophosphate was 1.0+/-0.3mum. These findings are discussed with reference to the control by luteinizing hormone of steroidogenesis from acetate.
mesh_terms: D000085:Acetates / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000475:Alkenes / Q000494:pharmacology; D000818:Animals; D002247:Carbon Isotopes; D006063:Chorionic Gonadotropin; D005204:Farnesol / Q000494:pharmacology; D005260:Female; D006064:Gonadotropins, Equine; D007700:Kinetics; D007986:Luteinizing Hormone / Q000494:pharmacology; D008274:Magnesium / Q000378:metabolism; D008798:Mevalonic Acid / Q000378:metabolism; D010053:Ovary / Q000201:enzymology*; D010060:Ovulation; D010756:Phosphoric Acids / Q000494:pharmacology; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D013256:Steroids / Q000096:biosynthesis; D013729:Terpenes / Q000494:pharmacology
chemical_list: D000085:Acetates; D000475:Alkenes; D002247:Carbon Isotopes; D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine; D010756:Phosphoric Acids; D013256:Steroids; D013729:Terpenes; D005204:Farnesol; D000255:Adenosine Triphosphate; D007986:Luteinizing Hormone; D010770:Phosphotransferases; D008274:Magnesium; D008798:Mevalonic Acid