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)

The activator of the D-serine deaminase operon, the product of the dsdC gene, has been partially purified. It is reasonably stable to routine purification procedures in the presence of its ligand D-serine, but not in its absence. It loses activity upon dialysis in amino acid-free buffer, but activity is completely restored upon readdition of D-serine. It apparently functions purely as an activator, no repressor function could be demonstrated at suboptimal D-serine concentration. It is a transcriptional control element. The time required for in vitro transcription of D-serine deaminase mRNA, nearly 4 min, is similar to that for beta-galactosidase. Since the beta-galactosidase monomer is a much protein, this is surprisingly long.
 ...
PMID:Role of the dsdC activator in regulation of D-serine deaminase synthesis. 21 19

During a simultaneous induction of three enzymes which are subject to catabolite repression (beta-galactosidase, tryptophanase and amylomaltase, or beta-galactosidase, tryptophanase and D-serine deaminase) in a batch culture, the rates of synthesis of beta-galactosidase and tryptophanase decreases, while the rates of synthesis of amylomaltase and D-serine deaminase remain unaffected. The addition of cAMP brings about a considerable increase of the rate of synthesis of D-serine deaminase and a partial synthesis rate increase of beta-galactosidase whihle the synthesis rate of tryptophanase remains lowered and the synthesis rate of amylomaltase remains unaffected. In a continuous culture beta-galactosidase, tryptophanase and D-serine deaminase are synthesized simultaneously at a maximum rate without mutual influence. The addition of cAMP increases the rate of synthesis of all three enzymes.
 ...
PMID:Simultaneous induction of three catabolic enzymes in Escherichia coli. 624 3

Intracellular concentration of cAMP regulates the synthesis of enzymes sensitive to catabolite repression. The relationship between the single and multiple induction of beta-galactosidase (EC 3.2.1.23), L-tryptophanase (EC 4.1.99.1), D-serine deaminase (EC 4.2.1.14), L-asparaginase (EC 3.5.1.1) and L-malate dehydrogenase (EC 1.1.1.37) was studied and the effect of cAMP level on the induction in Escherichia coli Crookes (ATCC 8739) was investigated. A varying degree of catabolite repression was observed during induction of individual enzymes induced separately on different energy sources. The synthesis of l-tryptophanase was most sensitive, whereas l-asparaginase was not influenced at all. Exogenous cAMP was found to overcome partially the catabolite repression of beta-galactosidase and D-serine deaminase, both during single induction. The synthesis of l-malate dehydrogenase was negatively influenced by the multiple induction even in the presence of cAMP; on the other hand, the synthesis of l-tryptophanase was stimulated, independently of the level of the exogenous cAMP. Similarly, the activity of L-asparaginase slightly but significantly increased during the multiple induction of all five enzymes; here too the activity increase did not depend on exogenous cAMP.
 ...
PMID:Catabolite repression during single and multiple induction in Escherichia coli. 625 31

Operon fusions between the D-serine deaminase regulatory and structural genes and lacZ were constructed and used to examine the control of expression of the positive regulatory gene, dsdC. Merodiploid strains containing both dsdCp::Mu d (lac Apr) and dsdC+A+ produced only one-fourth as much beta-galactosidase as did the haploid dsdCp::Mu d (lac Apr) strains, indicating that the dsdC+ product repressed its own synthesis. The repression was reversed by D-serine. dsdC expression was not depressed in a cya background. The basal level of D-serine deaminase was the same in wild-type and dsdCp fusion strains. The dsdC gene product was identified in maxicell strains harboring dsd plasmids as a 34,000-dalton protein. dsdC gene transcription proceeded clockwise; thus, its promoter is adjacent to that of dsdA.
 ...
PMID:Identification and control of synthesis of the dsdC activator protein. 629 57

It is reported that ethanol enhances DNA synthesis in E. coli cells [Basu, T and Poddar, R. K. (1994), Folia. Microbiol. 39, 3-6]. This communication reports that during growth of E. coli in the presence of 5% v/v ethanol, the derepressed expression of the cytoplasmic enzymes beta-galactosidase and D-serine deaminase per cell increased approximately three fold, while that of the periplasmic enzyme alkaline phosphatase decreased approximately 40% compared to control cell levels. However, in cells transformed with the plasmid pSM 456, bearing phoA-lacZ fusion, the level of induced synthesis of the hybrid protein PhoA-LacZ, controlled by the phoA promoter, was elevated by 25% in the presence of 5% v/v ethanol. This result suggests that the induction of the alkaline phosphatase precursor has also been enhanced by the ethanol treatment, but the inhibition in the export of the precursor across the cytoplasmic membrane, by the influence of ethanol, may represent the reason for the deficient expression of active alkaline phosphatase. It is proposed that there is an ethanol-mediated increase in DNA synthesis, resulting in gene amplification, which may enhance the synthesis of inducible proteins in ethanol-treated cells.
 ...
PMID:Over expression of inducible proteins in Escherichia coli by treatment with ethanol. 916 3