Purification and Properties of UDP-GlcNAc:Dolichyl-Pyrophosphoryl-GlcNAc GlcNAc Transferase from Mung Bean Seedling
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The N-acetylglucosamine (GlcNAc) transferase that catalyzes the formation of dolichyl-pyrophosphoryl-GlcNAc-GlcNAc from UDP-GlcNAc and dolichyl-pyrophosphoryl-GlcNAc was solubilized from the microsomal enzyme fraction of mung beans with 1.5% Triton X-100, and was purified 140-fold on columns of DE-52 and hydroxylapatite. The partially purified enzyme preparation was quite stable when stored in 20% glycerol and 0.5 millimolar dithiothreitol, and was free of GlcNAc-1-P transferase and mannosyl transferases. The GlcNAc transferase had a sharp pH optimum of 7.4 to 7.6 and the K(m) for dolichyl-pyrophosphoryl-GlcNAc was 2.2 micromolar and that for UDP-GlcNAc, 0.25 micromolar. The enzyme showed a strong requirement for the detergent Triton X-100 and was stimulated somewhat by the divalent cation Mg(2+). Uridine nucleotides, especially UDP and UDP-glucose inhibited the enzyme as did the antibiotic, diumycin. However, a variety of other antibiotics including tunicamycin were without effect. The product of the reaction was characterized as dolichyl-pyrophosphoryl-GlcNAc-GlcNAc.
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Ruiz-May E, Kim S, Brandizzi F, Rose J Front Plant Sci. 2012; 3:117.
PMID: 22685447 PMC: 3368311. DOI: 10.3389/fpls.2012.00117.
Drake R, Kaushal G, Pastuszak I, Elbein A Plant Physiol. 1991; 97(1):396-401.
PMID: 16668398 PMC: 1081011. DOI: 10.1104/pp.97.1.396.
Riedell W, Miernyk J Plant Physiol. 1988; 87(2):420-6.
PMID: 16666157 PMC: 1054767. DOI: 10.1104/pp.87.2.420.