title: Activity of the enzymes involved in the synthesis of exopolysaccharide precursors in an overproducing mutant ropy strain of Streptococcus thermophilus.
abstract: The activities of some enzymes belonging to the Leloir pathway, phosphoglucomutase, UDP-glucose pyrophosphorylase, UDP-galactose 4-epimerase and galactose 1-P uridyl transferase, were studied in a wild ropy, a non-ropy and an overproducing mutant ropy strain of Streptococcus thermophilus. These activities were assayed over successive culture transfers along with exocellular polysaccharide (EPS) production. The overproducing mutant ropy strain showed increments in polysaccharide production over successive culture transfers, as opposed to reductions in production by the wild ropy strain. The observed variations among strains in the enzyme activities that were analysed in relation to EPS production suggest their involvement in the synthesis of sugar-nucleotide EPS precursors.
authors: Departamento de Alimentos y Biotecnología, Lab. 312, Conjunto E, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, D.F. 04510, Mexico.
authors: Adelfo
authors: A
authors: Escalante
authors: Jesús
authors: J
authors: Villegas
authors: Carmen
authors: C
authors: Wacher
authors: Mariano
authors: M
authors: García-Garibay
authors: Amelia
authors: A
authors: Farrés
mesh_terms: D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D009154:Mutation / Q000502:physiology; D010641:Phenotype; D010733:Phosphoglucomutase / Q000235:genetics* / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics*; D014534:UDPglucose 4-Epimerase / Q000235:genetics / Q000378:metabolism; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000235:genetics / Q000378:metabolism; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase / Q000235:genetics / Q000378:metabolism
chemical_list: D011135:Polysaccharides, Bacterial; C098632:exopolysaccharide, Streptococcus; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase; D014534:UDPglucose 4-Epimerase; D010733:Phosphoglucomutase