title: [Isolation and properties of macrotetrolide synthase from the mycelium of Actinomycetes].
abstract: The formation of cyclic polyester antibiotics (macrotetrolides) from nactinic acids in a cell-free system in the presence of a mycelium homogenate of Streptomyces chryzomallus var. macrotetrolidi, a producer of a complex of homologous macrotetrolide antibiotics, was demonstrated. An enzyme catalyzing the formation of an ester macrotetrolide ring and possessing a specific activity of 360 mumol/min/mg of protein has been isolated for the first time from the mycelium homogenate and purified 176-fold with a 18% yield. Macrotetrolide synthase represents a macromolecular complex with a molecular mass of 360 kDa formed by several heterogeneous polypeptides. The effects of physico-chemical environmental factors on the stability and activity of the enzyme were demonstrated. The optimal conditions for the manifestation of the synthase activity (10 mM Tris-HCl, pH 8.0, 10% ethanol, 2% glycerol, 200 micrograms/ml of nactinic acids) were selected. The kinetic parameters of the enzyme-catalyzed macrotetrolide synthesis reaction (Km = 2.9.10(-4) M, V = 22.3 microM/min) were determined.
authors.forename: M V
authors.initials: MV
authors.lastname: Nefelova
authors.forename: I Iu
authors.initials: IIu
authors.lastname: Karelina
authors.forename: A N
authors.initials: AN
authors.lastname: Sverdlova
authors.forename: N S
authors.initials: NS
authors.lastname: Egorov
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D019729:Carbon-Oxygen Ligases; D002850:Chromatography, Gel; D004795:Enzyme Stability; D007700:Kinetics; D008025:Ligases / Q000302:isolation & purification* / Q000378:metabolism; D018942:Macrolides; D009097:Multienzyme Complexes / Q000302:isolation & purification / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D009097:Multienzyme Complexes; D008025:Ligases; D019729:Carbon-Oxygen Ligases; C063475:macrotetrolide synthase
vernacular_title: Vydelenie i svoĭstva sintazy makrotetrolidov iz mitseliia aktinomitseta--produtsenta.