title: Protection of hexaprenyl-diphosphate synthase of Micrococcus luteus B-P 26 against inactivation by sulphydryl reagents and arginine-specific reagents.
abstract: Hexaprenyl-diphosphate synthase from Micrococcus luteus B-P 26 has been shown to comprise two essential components, designated as components A and B. Treatment of the synthase with sulphydryl reagents (N-ethylmaleimide, iodoacetamide or p-chloromercuribenzoate) or arginine-specific reagents (2,3-butanedione, 1,2-cyclohexanedione or phenylglyoxal) resulted in a rapid loss of the component B activity. In contrast, component A was resistant to treatment with such reagents, retaining the initial activity almost completely. Farnesyl diphosphate, isopentenyl diphosphate, farnesyl monophosphate and inorganic pyrophosphate protected the synthase against the inactivation by N-ethylmaleimide, farnesyl diphosphate being the most effective. The presence of Mg2+ was essential for the protection by isopentenyl diphosphate and inorganic pyrophosphate. For protection of the synthase activity against the inactivation by 2,3-butanedione, the presence of farnesyl diphosphate, isopentenyl diphosphate and Mg2+ was more effective than that of the individual substrates and Mg2+. Inorganic pyrophosphate provided substantial protection. In the absence of component A, the component B activity was not protected by any substrates or its analogue. These results suggest that the catalytic site of the synthase is formed by cooperative interaction between components A and B, and that cysteine and arginine residues on component B play important roles in the synthase activity.
authors.affiliation: Chemical Research Institute of Non-Aqueous Solutions, Tohoku University, Sendai, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Koyama
authors.forename: K
authors.initials: K
authors.lastname: Ogura
mesh_terms: D000447:Aldehydes / Q000494:pharmacology*; D019883:Alkyl and Aryl Transferases; D001120:Arginine; D002074:Butanones / Q000494:pharmacology*; D002729:Chloromercuribenzoates / Q000494:pharmacology; D003510:Cyclohexanes / Q000494:pharmacology*; D003512:Cyclohexanones / Q000494:pharmacology*; D003931:Diacetyl / Q000494:pharmacology*; D004122:Dimethylallyltranstransferase / Q000378:metabolism*; D011756:Diphosphates / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005033:Ethylmaleimide / Q000494:pharmacology; D045782:Hemiterpenes; D007460:Iodoacetamide / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008837:Micrococcus / Q000201:enzymology*; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010658:Phenylglyoxal / Q000494:pharmacology*; D011106:Polyisoprenyl Phosphates / Q000494:pharmacology; D012717:Sesquiterpenes; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D014166:Transferases / Q000378:metabolism*; D020245:p-Chloromercuribenzoic Acid
chemical_list: D000447:Aldehydes; D002074:Butanones; D002729:Chloromercuribenzoates; D003510:Cyclohexanes; D003512:Cyclohexanones; D011756:Diphosphates; D045782:Hemiterpenes; D009943:Organophosphorus Compounds; D011106:Polyisoprenyl Phosphates; D012717:Sesquiterpenes; D013439:Sulfhydryl Reagents; C059195:farnesyl monophosphate; C004809:isopentenyl pyrophosphate; D020245:p-Chloromercuribenzoic Acid; C018031:1,2-cyclohexanedione; C004808:farnesyl pyrophosphate; D001120:Arginine; D014166:Transferases; D019883:Alkyl and Aryl Transferases; D004122:Dimethylallyltranstransferase; C036826:trans-pentaprenyltranstransferase; D008274:Magnesium; D003931:Diacetyl; D010658:Phenylglyoxal; D005033:Ethylmaleimide; D007460:Iodoacetamide