McIntosh C A, Latchinian L, Mansell R L
Department of Biology, University of South Florida, Tampa 33620.
Arch Biochem Biophys. 1990 Oct;282(1):50-7. doi: 10.1016/0003-9861(90)90085-d.
The isolation and characterization of a flavanone-specific 7-O-glucosyltransferase and its resolution from other glucosyltransferases in Citrus paradisi (grapefruit) seedlings is described. This new enzyme in the subclass 2.4.1 catalyzes the glucosylation of the 7-OH group of naringenin (4',5',7-trihydroxyflavanone) to prunin and has been purified (943-fold) by fractional precipitation with ammonium sulfate and successive chromatography on Sephadex G-100, hydroxyapatite, UDP-glucuronic acid agarose, Mono Q, and Mono P columns. It has a pH optimum of 7.5-8.0, an apparent pI of 4.3, and an apparent Mr of 54,900. This glucosyltransferase has an expressed specificity for the 7-position of the flavanones naringenin (Kmapp 62 microM; Kmapp UDPG 51 microM) and hesperetin (Kmapp 124 microM; Kmapp UDPG 243 microM) and did not accept other flavone or flavonol aglycones. Characteristics of other flavonoid glucosyltransferase activities found in grapefruit seedlings are also described.
本文描述了从葡萄柚（Citrus paradisi）幼苗中分离和鉴定一种黄烷酮特异性7-O-葡萄糖基转移酶，并将其与其他葡萄糖基转移酶区分开来的过程。这种2.4.1亚类中的新酶催化柚皮素（4',5',7-三羟基黄烷酮）7-OH基团糖基化为樱草糖苷，并已通过硫酸铵分级沉淀以及在Sephadex G-100、羟基磷灰石、UDP-葡萄糖醛酸琼脂糖、Mono Q和Mono P柱上连续色谱法纯化（943倍）。它的最适pH为7.5 - 8.0，表观pI为4.3，表观Mr为54,900。这种葡萄糖基转移酶对黄烷酮柚皮素（Kmapp 62 μM；Kmapp UDPG 51 μM）和橙皮素（Kmapp 124 μM；Kmapp UDPG 243 μM）的7位具有明显的特异性，不接受其他黄酮或黄酮醇苷元。文中还描述了在葡萄柚幼苗中发现的其他类黄酮葡萄糖基转移酶活性的特征。
