Identification of an ADPG-dependent trehalose synthase in Saccharomyces

Summary Uridine diphosphoglucose is not the sole donor for trehalose synthesis in yest cells: an ADPG-dependent trehalose synthase, has been identified in mutant strains with undetectable UDPG-dependent trehalose-6-P synthase activity. Genetic and chromatographic studies indicate that the two activities correspond to different proteins. The apparent K K_m for the nucleotide is similar for both enzymes, and Mg²⁺ is also required for both activities; however, a striking difference was observed with respect to ATP.Mg activation. This newly determined enzymatic activity in Saccharomyces clarifies previous contradictory results with mutant strains that are able to accumulate trehalose during growth yet whose UDPG-dependent trehalose synthase activity is undetectable in vitro.Abbreviations PMSF Phenyl-methyl-sulfonyl fluoride - EDTA ethileno-daminotetracetic acid - G6P glucose-6-phosphate - UDPG uridine5-diphosphoglucose - ADPG adenosine-5-diphosphoglucose - UDP uridine-5-diphosphate - ADP adenosine-5-diphosphate - PEP phosphoenol pyruvate - ATP adenosine-5-triphosphate - UTP uridine-5triphosphate - Pi inorganic phosphate - MOPS 3 (N-morpholino) propanesulfonic acid - PNPG paranitrophenylglucoside