RT Journal Article SR Electronic(1) A1 Beauvais, A. A1 Drake, R. A1 Ng, K. A1 Diaquin, M. A1 Latgé, J. P.YR 1993 T1 Characterization of the 1,3-β-glucan synthase of Aspergillus fumigatus JF Microbiology, VO 139 IS 12 SP 3071 OP 3078 DO https://doi.org/10.1099/00221287-139-12-3071 PB Microbiology Society, SN 1465-2080, AB 1,3-β-Glucan synthase activity has been detected in a membrane fraction extracted from the mycelium of the filamentous fungus Aspergillus fumigatus. The enzyme was solubilized by CHAPS and stabilized by filtration on a Bio-gel P30 column. Highest activity was obtained in the early exponential phase of growth. Four factors - GTP, NaF, sucrose and EDTA - added during the extraction procedure, were essential for optimal 1,3-β-glucan synthase activity. The soluble enzyme preparation was photolabelled with 5-azido-[32P]UDP-glucose and 5-125IASA-UDP-glucose which bind covalently to the enzyme after UV irradiation. These UDP-glucose substrate analogues were competitive inhibitors of the enzyme with a K i of 1·42 mm and 0·3 mm for 5-azido-UDP-glucose and 5-ASA-UDP-glucose, respectively (K m for UDP-glucose = 1·9 mm). Potential UDP-glucose-binding polypeptides were identified with molecular masses of 31, 50 and 115 kDa., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-139-12-3071