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)

Bacillus subtilis B secretes an inducible, extracellular enzyme, levansucrase. Inhibition studies were undertaken to investigate the possible mechanism of release of this enzyme. The antibiotic cerulenin, at a concentration of 10 micrograms/ml, totally inhibited de novo lipid synthesis in B. subtilis B for at least 1 h, while only slightly reducing protein and RNA synthesis. At this concentration cerulenin, added concomitantly with the inducer sucrose, prevented the release of levansucrase for at least 150 min. This was not due to the prevention of inducer uptake by the cells. The release of the enzyme was also independent of cell division. In B. subtilis 1007 the induction of beta-galactosidase by 5 mM lactose was not prevented by cerulenin. Preliminary evidence indicated the association of a lipid moiety with the enzyme as it passes through the cytoplasmic membrane. Quinacrine (0.2 mM), which inhibits the penicillinase-releasing protease of Bacillus licheniformis, inhibited levansucrase release from B. subtilis B, but had no effect on lipid synthesis.
 ...
PMID:Export of extracellular levansucrase by Bacillus subtilis: inhibition by cerulenin and quinacrine. 10 56

Subtilisin expression as a function of growth and sporulation was determined using a presubtilisin-beta-galactosidase gene fusion. An approximately 500-base-pair region upstream of the subtilisin gene and including the first eight codons of the presubtilisin protein was fused at the eighth codon of beta-galactosidase in the integrative vector pJF751. This gene fusion does not carry a signal sequence, and therefore its synthesis is uncoupled from maturation of presubtilisin. The fusion protein gene was integrated into a variety of recipient strains to test for the effect of various mutations on the initial rate of presubtilisin-beta-galactosidase synthesis. Among the spo0 mutations tested, the spo0A mutations showed a strong, 10-fold decrease in the rate of beta-galactosidase synthesis. This effect of the spo0A mutations was not evident when the presubtilisin-beta-galactosidase fusion was present on a multicopy plasmid. The sacU mutation, which was known to increase the extracellular level of levansucrase and proteases, was found to increase the synthesis of the presubtilisin-beta-galactosidase gene fusions 7-fold, and the hpr mutations were shown to increase the rate of presubtilisin-beta-galactosidase gene fusions 17-fold, indicating that these mutations influence either transcription or translation of the presubtilisin gene. However, the effect of these mutations was only observed in the stationary phase of growth, indicating they did not render synthesis constitutive. By using multicopy plasmids and an integrated gene fusion, it was shown that there is likely to be a titratable repressor controlling subtilisin synthesis.
 ...
PMID:Effect of stage 0 sporulation mutations on subtilisin expression. 308 52

Using pBR322- and pUC-derived plasmid vectors, a homologous (Escherichia coli native esterase) and three heterologous proteins (human interleukin-2, human interleukin-6, and Zymomonas levansucrase) were synthesized in E. coli IC2015(recA::lacZ) and GY4786 (sfiA::lacZ) strains. Via time-course measurement of beta-galactosidase activity in each recombinant culture, the SOS induction was estimated in detail and the results were systematically compared. In recombinant E. coli, the SOS response did not happen either with the recombinant insert-negative plasmid backbone alone or the expression vectors containing the homologous gene. Irrespective of gene expression level and toxic activity of synthesized foreign proteins, the SOS response was induced only when the heterologous genes were expressed using a particular plasmid vector, indicating strong dependence on the recombinant gene clone and the selection of a plasmid vector system. It is suggested that in recombinant E. coli the SOS response (i.e., activation of recA expression and initial sfiA expression) may be related neither to metabolic burden nor toxic cellular event(s) by synthesized heterologous protein, but may be provoked by foreign gene-specific interaction between a foreign gene and a plasmid vector. Unlike in E. coli XL1-blue(recA(-)) strains used, all expression vectors encoding each of the three heterologous proteins were multimerized in E. coli IC2015 strains in the course of cultivation, whereas the expression vectors containing the homologous gene never formed the plasmid multimers. The extent of multimerization was also dependent on a foreign gene insert in the expression vector. As a dominant effect of the SOS induction, recombinant plasmid vectors used for heterologous protein expression appear to significantly form various multimers in the recA(+) E. coli host.
 ...
PMID:Interplay of SOS induction, recombinant gene expression, and multimerization of plasmid vectors in Escherichia coli. 1220 89