Saccharomyces fragilis

As evidence for reaction (1), 1 mole of D-glucosyl phosphate was formed per mole of UDP-glucose and D-galactosyl phosphate consumed when the last two compounds were incubated with an extract of Saccharomyces fragilis.13,w Experiments188 with C14-labeled D-glucosyl phosphate also favor the mechanism represented by reactions (1) and (2). 

Most of our present information on the conversion of galactose to glucose has come from the study of microorganisms, particularly the yeast Saccharomyces fragilis. However, there is ample evidence that the same metabolic paths are followed in mammalian tissue. 

A similar reaction had previously been known to occur in Saccharomyces fragilis (K8) and in bean seedlings (N3). This is an alternative route to UDPGal, but the activity of the enzyme in newborn liver is very low even in the adult it is only one-sixth that of galactose-l-phosphate uridyl transferase (13), as shown in Table 2. 

It would appear that the specific action of an enzyme upon its substrate is conditioned by a definite chemical structure and spatial arrangement of the constituent polar and non-polar groups of the enzyme protein as well as by the constitution and configuration of the substrate. In some cases an enzyme interacts with one chemical compound only. For example, galactokinase extracted from Saccharomyces fragilis (grown on whey) catalyzes the transphosphorylation between adenosine triphos-... 

Wasserman, A. E. 1960A. Whey utilization. II. Oxygen requirements of Saccharomyces fragilis growing in whey medium. AppL MicrobioL 8, 291-293. 

Wasserman, A. E. 1960B. Whey utilization. IV. Availability of whey nitrogen for the growth of Saccharomyces fragilis. J. Dairy Sci. 43, 1231-1234. 

Wasserman, A. E. and Hampson, J. W. 1960. Whey utilization. III. Oxygen absorption rates and the growth of Saccharomyces fragilis in severed propagators. AppL Microbiol. 8, 293-297. 

Wasserman, A. E., Hopkins, W. J. and Porges, N. 1958. Whey utilization—growth conditions for Saccharomyces fragilis. Sewage Ind. Wastes 30, 913-920. 

Wendorff, W. L., Amundson, C. H. and Olson, N. F. 1970. Nutrient requirement and growth conditions for production of lactase enzyme by Saccharomyces fragilis. J. Milk Food Technol. 33, 451-455. 

Saccharomyces fragilis -inhibited by sorbates [SORBIC ACID] (Vol 22) -inhibited by sorbates [SORBIC ACID] (Vol 22)... 

J. P. F. Tijssen, H. W. Beekes and J. Van Steveninck (1982). Localization of polyphosphate in Saccharomyces fragilis, as revealed by 4,6,-diamidino-2-phenylindole fluorescence. Biochem. 

The information given in this Chapter is based chiefly on studies with relatively few kinds of yeast, the most popular of which have been Saccharomyces cerevisiae, Saccharomyces uvarum (synonymous with Saccharomyces carlsbergensis), Candida utilis (that is, Torulopsis or Torula utilis), and Kluyveromyces (Saccharomyces) fragilis.91... 

The monosaccharide carriers of Saccharomyces cerevisiae, and also of Kluyveromyces (Saccharomyces) fragilis, appear from polarimetric measurements to have a higher affinity for the a-D anomers of D-glucose, D-mannose, and D-xylose than for the corresponding /3 anomers.178 Intracellularly, a-D-glucopyranose is a slightly better substrate of hexokinase than the /3 anomer.179... 

At equilibrium, D-galactopyranose is present in aqueous solution as about 27% a anomer and 73% /3 anomer,3123 and transport into cells has been reported as not specific for either form for Sac-charomyces cerevisiae and Kluyveromyces (Saccharomyces) fragilis, grown on complex media.312 1 Within the cells, aldose 1-epimerase (EC 5.1.3.3) converts /3-D-galactose into the a anomer312 1 for which galactokinase activity is highly specific.325... 

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