Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1,3)-beta-D-Glucan synthase of Candida albicans was rendered soluble by treatment of membrane preparations with the polyoxyethylene ether detergent W-1. Extraction with 0.025% W-1 at 4 degrees C for 24 h effectively solubilized and activated the enzyme. Under these conditions, greater than 85% of the protein in membrane preparations was released, and about 64% of the glucan synthase activity could be recovered in the soluble form. Soluble enzyme activity was stable for more than 12 days at 4 degrees C. Also, glucan synthase activity in the extracted membrane preparations could be activated to achieve more than twice the enzyme activity in the original, unextracted membrane preparations. The soluble glucan synthase had characteristics similar to those of the membrane-bound enzyme. Soluble glucan synthase had an apparent Km of 2.0 mM, and particulate glucan synthase had an apparent Km of 2.5 mM. Kinetics of cilofungin inhibition for both enzyme preparations were noncompetitive, with an apparent Ki of 2.5 microM; both preparations could be inhibited by cilofungin but not by its peptide nucleus or side chain, either alone or in combination. The reaction products from both forms of the enzyme were sensitive to (1,3)-beta-D-glucanase degradation but not to alpha-amylase, alpha-glucosidase, or proteinase K degradation and thus were shown to be beta(1----3) glucan.
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PMID:W-1 solubilization and kinetics of inhibition by cilofungin of Candida albicans (1,3)-beta-D-glucan synthase. 182 95

Novel mutations in the RSW1 and KNOPF genes were identified in a large-scale screen for mutations that affect cell expansion in early Arabidopsis embryos. Embryos from both types of mutants were radially swollen with greatly reduced levels of crystalline cellulose, the principal structural component of the cell wall. Because RSW1 was previously shown to encode a catalytic subunit of cellulose synthase, the similar morphology of knf and rsw1-2 embryos suggests that the radially swollen phenotype of knf mutants is largely due to their cellulose deficiency. Map-based cloning of the KNF gene and enzyme assays of knf embryos demonstrated that KNF encodes alpha-glucosidase I, the enzyme that catalyzes the first step in N-linked glycan processing. The strongly reduced cellulose content of knf mutants indicates that N-linked glycans are required for cellulose biosynthesis. Because cellulose synthase catalytic subunits do not appear to be N glycosylated, the N-glycan requirement apparently resides in other component(s) of the cellulose synthase machinery. Remarkably, cellular processes other than extracellular matrix biosynthesis and the formation of protein storage vacuoles appear unaffected in knf embryos. Thus in Arabidopsis cells, like yeast, N-glycan trimming is apparently required for the function of only a small subset of N-glycoproteins.
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PMID:Alpha-glucosidase I is required for cellulose biosynthesis and morphogenesis in Arabidopsis. 1190 Nov 67