Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

KB cells were synchronized by a double thymidine block procedure. An investigation was made of the activities of alpha-L-fucosidase (EC 3.2.1.51), alpha-D-galactosidase (EC 3.2.1.22), beta-D-galactosidase (ec 3.2.1.23), alpha-D-glucosidase (EC 3.2.1.20), beta-D-glucosidase (EC 3.2.1.21), alpha-D-mannosidase (EC 3.2.1.24), beta-D-N-acetylgalactosaminidase (EC 3.2.1.53), and beta-D-N-acetylglucosaminidase (EC 3.2.1.52) from synchronized cultures, using appropriate artificial substrates. Ceramide glucosidase (EC 3.2.1.45) and ceramide trihexosidase levels (EC 3.2.1.47) were also investigated at various stages in the cell cycle, using appropriate glycosphingolipid substrates. Whereas each of these enzymes exhibited some activity throughout the cell cycle, peak activity (2- to 6-fold increase) occurred late in the S phase. Two molecular forms of ceramide glucosidase (optimal activity at pH 4.0 and pH 6.0) and two forms of ceramide trihexosidase (pH 4.0 and pH 7.5) were identified. Peak levels of the forms that preferred the relatively acid pH occurred earlier in the S phase of the cell cycle than those of the forms that were more active at the higher pH. The possibility that the forms with optimal activity at pH 4 are precursors of those with optimal activity at pH 6 to 7.5 is discussed. Precipitation of beta-galactosidase of synchronized KB cells with specific antibody revealed that changes in the activity of this enzyme during the cell cycle were the result of fluctuations in the amount of the enzyme.
 ...
PMID:Glycosphingolipid glycosyl hydrolases and glycosidases of synchronized human KB cells. 115 Jun 49

The activation of sphingomyelinase, galactosyl- and lactosylceramide beta-galactosidases, GM1, beta-galactosidase, cerebroside sulphate sulphatase, trihexosylceramide alpha-galactosidase and globoside beta-hexosaminidase by a number of bile salts was studied. Most of the salts examined, except glycolithocholate and deoxycholate, were effective activators of enzyme activity. Pure, but not crude, taurocholate elicited poor trihexosylceramide alpha-galactosidase and cerebroside sulphate sulphatase activities. The bile salt activation was often dependent on a number of parameters including the bile salt concentraion, pH, protein to bile salt ratio, and the nature of the enzyme preparation. In the absence of bile salts, Triton X-100 induced little activity of any of the hydrolases except sphingomyelinase; in their presence however, Triton either promoted or inhibited the activation depending on the enzyme. Our data suggest that bile salt structure is an important factor in determining the degree of activation of individual hydrolases and that this may be due to intramicellar lipid substrate/bile salt interactions, which either facilitate or inhibit the corresponding enzyme reaction.
 ...
PMID:The bile salt activation of leucocyte sphingolipid hydrolase activity and the modifying effects of triton X-100. 610 84