RT Journal Article SR Electronic(1) A1 McCann, A. Kate A1 Hilberg, F. A1 Kenworthy, P. A1 Barnett, J. A.YR 1987 T1 An Unusual Hexose-ATP-Kinase with Two Catalytic Sites and a Role in Carbon Catabolite Repression in the Yeast Schwanniomyces occidentalis JF Microbiology, VO 133 IS 2 SP 381 OP 389 DO https://doi.org/10.1099/00221287-133-2-381 PB Microbiology Society, SN 1465-2080, AB The hexose-ATP-kinase of wild-type Schwanniomyces occidentalis (CBS 819) is, like hexokinase PII of Saccharomyces cerevisiae, associated with carbon catabolite repression and phosphorylates d-glucose and d-fructose. The kinase of Schw. occidentalis repression-resistant (DogR) mutants phosphorylates d-glucose, but not d-fructose. Subjecting the wild-type enzyme to 45 °C for a few minutes appears to alter its activity, specificity and kinetic characteristics to that of the mutant enzyme. Fast protein liquid chromatography, with anion-exchange or gel-filtration columns, gel-electrophoresis, and DNA hybridization with the hexl r mutant of the HXK2 (hexokinase PII) gene of Sacch. cerevisiae, all failed to resolve more than one hexose-ATP-kinase in Schw. occidentalis. Hence Schw. occidentalis appears to have a single hexose-ATP-kinase, M r ∼ 72000, with two catalytic sites, analogous to the aspartate kinase/homoserine dehydrogenase of Escherichia coli. One site is hexokinase-like and associated with catabolite repression and the other is glucokinase-like. Values for apparent K m were 7·2 mm-d-fructose and 0·55 mm-d-glucose (hexokinase site) and 0·078 mm-d-glucose (glucokinase site)., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-133-2-381