Genetic control of UDP-glucose: anthocyanin 5-O-glucosyltransferase from flowers ofMatthiola incanaR.Br.

✍ Scribed by M. Teusch; G. Forkmann; W. Seyffert

• Publisher: Springer-Verlag
• Year: 1986
• Tongue: English
• Weight: 607 KB
• Volume: 168
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00392280

✦ Synopsis

In flower extracts of defined genotypes of Matthiola incana, an enzyme was demonstrated which catalyzes the transfer of the glucosyl moiety of uridine 5'-diphosphoglucose (UDPGlc) to the 5-hydroxyl group of pelargonidin and cyanidin 3-glycosides and acylated derivatives. The best substrate for 5-glucosylation is the 3-xylosylglucoside acylated with p-coumarate, followed by the 3-xylosylglucoside and by the acylated (p-coumarate) 3-glucoside. The 3-glucoside itself is a very poor substrate. Besides UDPGlc, thymine 5'-diphosphoglucose is a suitable glucosyl-donor, but with a reduced reaction rate (42%). The anthocyanin 5-O-glucosyltransferase exhibits a pH optimum at 7.5 and is generally inhibited by divalent ions and by ethylenediaminetetraacetic acid and p-chloromercuribenzoate. Investigations on different genotypes showed that the 5-O-glucosyltransferase activity is clearly controlled by the gene l. In confirmation of earlier chemogenetic work, enzyme activity is only present in lines with the wild-type allele l(+). The anthocyanin 5-O-glucosyltransferase activity is strictly correlated with the formation of 5-glucosylated anthocyanins during bud development.