Biosynthesis of the isoprenoid precursor isopentenyl diphosphate (IPP) proceeds via two distinct pathways. Sequence comparisons and microbiological data suggest that multidrug-resistant strains of gram-positive cocci employ exclusively the mevalonate pathway for IPP biosynthesis. Bacterial mevalonate pathway enzymes therefore offer potential targets for development of active site-directed inhib...

The acyltransferase (AT) domain in module 4 of the erythromycin polyketide synthase (PKS) was substituted with an AT domain from the rapamycin PKS module 2 in order to alter the substrate specificity from methylmalonyl-CoA to malonyl-CoA. The resulting strain produced 6-desmethyl erythromycin D as the predominant product. This AT domain swap completes the library of malonyl-CoA AT swaps on the ...

Cultured cells of Picea excelsa capable of forming stilbenes and flavanoids have been established. Unlike needles of intact plants containing piceatannol (3,3',4',5-tetrahydroxystilbene) and stilbene glycosides the cultured cells converted phenylalanine and p-coumaric acid primarily into resveratrol monomethyl ether (3,4'-dihydroxy-5-methoxystilbene) and naringenin. Partially purified enzyme pr...

2. p-Coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA were found to be efficient substrates of the synthase. The products formed were naringenin (5,7,4'-trihydroxyflavanone), eriodictyol (5,7,3',4'-tetrahydroxyflavanone) and homoeriodictyol (5,7,4'-trihydroxy-3'-methoxyflavanone), re­ spectively. Addition of thiol reagents at concentrations exceeding 10~ 3 m caused inhibition of the enzyme. “Releas...

A thioesterase present in the uropygial gland of mallard functions in conjunction with fatty acid synthase to produce short chain acids in this gland (deRenobales, M., Rogers, L., and Kolattukudy, P. E. (1980) Arch. Biochem. Biophys. 205,464-477). This enzyme, capable of releasing short chain acids from fatty acid synthase, was purified to near homogeneity. This S-acyl fatty acid synthase thioe...

Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (EC 4.1.3.5) was purified to homogeneity from ox liver and obtained essentially free from acetoacetyl-CoA thiolase activity. The purification procedure included substrate elution from cellulose phosphate and chromatofocusing. The relative molecular mas was about 100 000 and S20,w0 was 6.36S. The enzyme appears to be a dimer of identical subu...

Polyhydroxybutyrate (PHB) synthases catalyze the polymerization of (R)-3-hydroxybutyryl-CoA (HB-CoA) into high molecular weight PHB, biodegradable polymers. The class III PHB synthase from Allochromatium vinosum is composed of a 1:1 mixture of two approximately 40 kDa proteins: PhaC and PhaE. Previous studies using site-directed mutagenesis and a saturated trimer of hydroxybutyryl-CoA have sugg...

The ThYme (Thioester-active enzYme; http://www.enzyme.cbirc.iastate.edu) database has been constructed to bring together amino acid sequences and 3D (tertiary) structures of all the enzymes constituting the fatty acid synthesis and polyketide synthesis cycles. These enzymes are active on thioester-containing substrates, specifically those that are parts of the acyl-CoA synthase, acyl-CoA carbox...

The pathway of anaerobic toluene oxidation to benzoyl coenzyme A (benzoyl-CoA) consists of an initial reaction catalyzed by benzylsuccinate synthase, a glycyl radical enzyme adding the methyl group of toluene to the double bond of a fumarate cosubstrate, and a subsequent beta-oxidation pathway of benzylsuccinate. Benzylsuccinate synthase has been studied in some detail, whereas the enzymes part...