title: A hitherto unknown transketolase-catalyzed reaction.
abstract: Yeast transketolase, in addition to catalyzing the transferase reaction through utilization of two substrates--the donor substrate (ketose) and the acceptor substrate (aldose)--is also able to catalyze a one-substrate reaction with only aldose (glycolaldehyde) as substrate. The interaction of glycolaldehyde with holotransketolase results in formation of the transketolase reaction intermediate, dihydroxyethyl-thiamin diphosphate. Then the glycolaldehyde residue is transferred from dihydroxyethyl-thiamin diphosphate to free glycolaldehyde. As a result, the one-substrate transketolase reaction product, erythrulose, is formed. The specific activity of transketolase was found to be 0.23 U/mg and the apparent Km for glycolaldehyde was estimated as 140 mM.
authors.affiliation: ANBelozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, GSP-2, Russia.
authors.forename: Irina A
authors.initials: IA
authors.lastname: Sevostyanova
authors.forename: Olga N
authors.initials: ON
authors.lastname: Solovjeva
authors.forename: German A
authors.initials: GA
authors.lastname: Kochetov
mesh_terms: D000079:Acetaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry; D001669:Biochemical Phenomena; D001671:Biochemistry; D002384:Catalysis; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013997:Time Factors; D014174:Transketolase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014174:Transketolase; D000079:Acetaldehyde; C010972:glycolaldehyde