Biomaterial Database

Biosynthesis of bacterial menaquinones: the membrane-associated 1,4-dihydroxy-2-naphthoate octaprenyltransferase of Escherichia coli. 1976

B Shineberg, and I G Young

It has been postulated that 1,4-dihydroxy-2-naphthoic acid is the naphthalenic intermediate in the biosynthesis of menaquinone (vitamin K2) in Escherichia coli to which the octaprenyl side chain is attached to from demethylmenaquinone. In the present work the presence of enzyme, 1,4-dihydroxy-2-naphthoate octaprenyltransferase, which catalyzes the conversion of 1,4-dihydroxy-2-naphthoate to demethylmenaquinone was demonstrated in cell extracts of E. coli. Demethylmenaquinone-9 was formed when the naphthoate was incubated with cell extracts and the synthetic substrate, solanesyl pyrophosphate, in the presence of Triton X-100. Solanesyl monophosphate could not substitute for the pyrophosphate in the reaction. The prenylation of of 1,4-dihydroxy-2-naphthoate was also studied in a strain of E. coli which accumulates octaprenyl pyrophosphate, the natural precursor of the menaquinone side chain. The octaprenyltransferase was shown to be membrane bound and to require magnesium ions for optimal activity. A menA-mutant of E. coli was found to lack the octaprenyltransferase activity, suggesting that the menA gene is the structural gene for this enzyme. However, this strain had normal levels of 4-hydroxybenzoate octaprenyltransferase, the enzyme catalyzing the analogous prenylation reaction in ubiquinone biosynthesis, providing additional evidence that the two octaprenyltransferases are quite distinct.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D011092	Polyethylene Glycols	Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.	Macrogols,Polyoxyethylenes,Carbowax,Macrogol,Polyethylene Glycol,Polyethylene Oxide,Polyethyleneoxide,Polyglycol,Glycol, Polyethylene,Glycols, Polyethylene,Oxide, Polyethylene,Oxides, Polyethylene,Polyethylene Oxides,Polyethyleneoxides,Polyglycols,Polyoxyethylene
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D014166	Transferases	Transferases are enzymes transferring a group, for example, the methyl group or a glycosyl group, from one compound (generally regarded as donor) to another compound (generally regarded as acceptor). The classification is based on the scheme "donor:acceptor group transferase". (Enzyme Nomenclature, 1992) EC 2.	Transferase
D014812	Vitamin K	A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: VITAMIN K 1 (phytomenadione) derived from plants, VITAMIN K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, VITAMIN K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K.