Identification, properties, and genetic control of UDP-glucose: Cyanidin-3-rhamnosyl-(1→6)-glucoside-5-O-glucosyltransferase isolated from petals of the red campion(Silene dioica)

✍ Scribed by John Kamsteeg; Jan van Brederode; Gerrit van Nigtevecht

• Publisher: Springer
• Year: 1978
• Tongue: English
• Weight: 594 KB
• Volume: 16
• Category: Article
• ISSN: 0006-2928
• DOI: 10.1007/bf00484526

✦ Synopsis

An enzyme catalyzing the transfer of the glucosyl moiety of UDP-glucose to the 5-hydroxyl group of cyanidin-3-rhamnosyl-(1 leads to 6)-glucoside has been demonstrated in petal extracts of Silene dioica plants. This glucosyltransferase activity was not detectable in green parts of these plants. The enzyme activity is controlled by a single dominant gene M; no glucosyltransferase activity could be demonstrated in petals of m/m plants. The enzyme was purified eightyfold by PVP and Sephadex G50 chromatography. The glucosyltransferase had a pH optimum of 7.4, had a molecular weight of about 55,000, was stimulated by divalent metal ions, and had a "true Km" values of 0.5 x 10(-3) M for UDP-glucose and 3.6 x 10(-3) M for cyanidin-3-rhamnosylglucoside. Pelargonidin-3-rhamnosylglucoside also could serve as acceptor. The enzyme did not catalyze the glucosylation of the 5-hydroxyl group of cyanidin-3-glucoside, although in petals of M/- n/n mutants cyanidin-3,5-diglucoside is present. ADP-glucose could not serve as a glucosyl donor.