M-glycogenin, the protein moiety of Neurospora crassa proteoglycogen, is an auto- and transglucosylating enzyme.
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-alpha 1,4-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 Mn2+. 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.
Goldraij
A
A
Química Biológica de Córdoba (CIQUIBIC), UNC-CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córaoba, Argentina.
Curtino
J A
JA
D005947:Glucose / Q000378:metabolism*; D005964:Glucosyltransferases; D006001:Glycoconjugates / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism; D009492:Neurospora crassa / Q000378:metabolism*
D006001:Glycoconjugates; D006023:Glycoproteins; C051887:glycogenin; D008345:Manganese; D006003:Glycogen; D005964:Glucosyltransferases; D005947:Glucose