title: Identification and characterisation of a new human glucose-6-phosphatase isoform.
abstract: The liver endoplasmic reticulum glucose-6-phosphatase catalytic subunit (G6PC1) catalyses glucose 6-phosphate hydrolysis during gluconeogenesis and glycogenolysis. The highest glucose-6-phosphatase activities are found in the liver and the kidney; there have been many reports of glucose 6-phosphate hydrolysis in other tissues. We cloned a new G6Pase isoform (G6PC3) from human brain encoded by a six-exon gene (chromosome 17q21). G6PC3 protein was able to hydrolyse glucose 6-phosphate in transfected Chinese hamster ovary cells. The optimal pH for glucose 6-phosphate hydrolysis was lower and the K(m) higher relative to G6PC1. G6PC3 preferentially hydrolyzed other substrates including pNPP and 2-deoxy-glucose-6-phosphate compared to the liver enzyme.
authors.affiliation: Ninewells Hospital and Medical School, University of Dundee, DD1 9SY Dundee, UK.
authors.forename: Olivier
authors.initials: O
authors.lastname: Guionie
authors.forename: Eric
authors.initials: E
authors.lastname: Clottes
authors.forename: Kirsten
authors.initials: K
authors.lastname: Stafford
authors.forename: Ann
authors.initials: A
authors.lastname: Burchell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D040461:Gene Components; D005952:Glucose-6-Phosphatase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013379:Substrate Specificity; D014018:Tissue Distribution
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D005952:Glucose-6-Phosphatase