M-Glycogenin, the Protein Moiety of Neurospora crassa Proteoglycogen, Is an Auto- and Transglucosylating Enzyme

Publisher： Elsevier

ISSN： 0006-291X

Source： Biochemical and Biophysical Research Communications, Vol.227, Iss.3, 1996-10, pp. : 909-914

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Abstract

Neurospora crassa proteoglycogen was purified and its protein moiety, M-glycogenin, was released by amylolytic treatment. The released protein was capable of autoglucosylation from UDP-glucose forming glucosyl-alpha1,4-glucosyl linkage. The kinetics of autoglucosylation suggested an intramolecular mechanism of reaction. M-glycogenin was also able to glucosylate dodecyl-beta-maltoside and autoglucosylate, simultaneously and independently. Both auto- and transglucosylation reactions were dependent on Mn 2+ . Thus, M-glycogenin, which has also been described as the constituent of Escherichia coli proteoglycogen (A. Goldraij and J. A. Curtino, 1993, Biochem. Mol. Biol. Int. 30, 453-458), is a glucosyltransferase that bears similar catalytic properties with mammalian glycogenin. This is the first report on the enzymatic character of the protein constituent of proteoglycogen in primitive organisms, which suggest that the mechanism for the de novo biosynthesis of glycogen was conserved over a very long period of evolution.