Guillén A, Leal F, Andaluz E, Larriba G
Biochim Biophys Acta. 1985 Oct 17;842(2-3):151-61. doi: 10.1016/0304-4165(85)90197-7.
Yeast 1,3-beta-D-glucan synthetase (EC 2.4.1.34) activity is modulated by endogenous factors obtained by the extraction of different subcellular fractions with hot water. Cell wall fractions were enriched in activators while supernatant fractions also contained appreciable amounts of inhibitors. The action of these compounds requires the presence of EDTA. Maximal activation by the stimulatory material was reached when assayed in sonicated enzymatic preparations that had been obtained by mechanical breakage of cells in water. The activating material derived from cell wall fractions contained a mixture of low molecular weight compounds. They were found to be different from GTP as deduced from their resistance to alkaline phosphatase and different elution profile in gel filtration. The supernatant material was also heterogeneous with regard to both activators and inhibitors. The combined effect of GTP and activating material derived from cell wall fractions was supraadditive. The polymers synthesized in the absence and in the presence of the endogenous activator were characterized as beta-1,3-glucans on the base of their resistance to periodate and susceptibility to beta-glucanases. However, the length of the radioactive chains was greater when synthesized in the presence of the activator. This was mediated by an increase in the Vmax of the synthetase.
酵母1,3-β-D-葡聚糖合成酶（EC 2.4.1.34）的活性受通过用热水提取不同亚细胞组分获得的内源性因子调节。细胞壁组分富含激活剂，而上清液组分也含有相当数量的抑制剂。这些化合物的作用需要EDTA的存在。当在通过在水中机械破碎细胞获得的超声处理酶制剂中进行测定时，刺激物质达到最大激活。来自细胞壁组分的激活物质包含低分子量化合物的混合物。从它们对碱性磷酸酶的抗性和凝胶过滤中的不同洗脱谱推断，发现它们与GTP不同。上清液物质在激活剂和抑制剂方面也是异质的。GTP和来自细胞壁组分的激活物质的联合作用是超加性的。根据它们对高碘酸盐的抗性和对β-葡聚糖酶的敏感性，在不存在和存在内源性激活剂的情况下合成的聚合物被表征为β-1,3-葡聚糖。然而，当在激活剂存在下合成时，放射性链的长度更长。这是由合成酶Vmax的增加介导的。
