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)

Bovine zona pellucida (ZP) glycoproteins from ovarian egg emerged as three bands with molecular mass of 78 kDa, 64 kDa and 21 kDa in SDS-PAGE under reducing conditions. Endo-beta-galactosidase (E beta G) digestion of the glycoproteins yielded five products with molecular mass of 76 kDa (E beta G-76), 68 kDa (E beta G-68), 63 kDa (E beta G-63), 47 kDa (E beta G-47) and 21 kDa (E beta G-21) under the same conditions. The N-terminal amino acid sequences of E beta G-76 and E beta G-21 were identical. This fact together with the results of diagonal SDS-PAGE indicated that E beta G-21 (N-terminal region) is linked to E beta G-63 (C-terminal region) through disulfide bond to form E beta G-76. Immunoblot analysis using anti-pig ZP protein antibodies revealed that bovine E beta G-76, E beta G-68 and E beta G-47 correspond to pig PZP2, PZP3 alpha and PZP3 beta glycoproteins, respectively. The E beta G-76 and E beta G-68 components were shown to be specifically cleaved during fertilization.
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PMID:Characterization of the zona pellucida glycoproteins from bovine ovarian and fertilized eggs. 791 85

A genomic clone bank of Acetobacter polyoxogenes NBI1028 constructed in Escherichia coli by use of the expression vector pUC18 was screened with antibody raised against membrane-bound aldehyde dehydrogenase (ALDH; 75 kilodaltons [kDa]) from A. polyoxogenes NBI1028. A clone that synthesized a 41-kDa protein cross-reactive with anti-ALDH antibody was isolated. For cloning of the full-length ALDH structural gene, a cosmid gene bank was screened by Southern blot hybridization with the cloned DNA as a probe, and subcloning from the positive cosmid clone was performed with shuttle vector pMV24. Plasmid pAL25, containing the full-length ALDH structural gene, was isolated and expressed in both E. coli and Acetobacter aceti to produce a fused protein (78 kDa) with a short NH(2)-terminal beta-galactosidase peptide. pAL25 conferred ALDH production on a mutant of A. aceti lacking the enzyme activity. Transformation of A. aceti subsp. xylinum NBI2099 with pAL25 caused 2- and 1.4-fold increases in the production rate and in the maximum concentration of acetic acid in submerged fermentation, respectively.
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PMID:Cloning of the Membrane-Bound Aldehyde Dehydrogenase Gene of Acetobacter polyoxogenes and Improvement of Acetic Acid Production by Use of the Cloned Gene. 1634 20

beta-Galactosidase (EC: 3.2.1.23), one of the glycosidases detected in Erythrina indica seeds, was purified to 135 fold. Amongst the four major glycosidases detected beta-galactosidase was found to be least glycosylated, and was not retained by Con-A CL Seralose affinity matrix. A homogenous preparation of the enzyme was obtained by ion-exchange chromatography, followed by gel filtration. The enzyme was found to be a dimmer with a molecular weight of 74 kDa and 78 kDa, by gel filtration and SDS-PAGE, respectively. The optimum pH and optimum temperature for enzyme activity were 4.4 and 50 degrees C, respectively. The enzyme showed a K(m) value of 2.6 mM and V(max) of 3.86 U/mg for p-nitrophenyl-beta-D-galactopyranoside as substrate and was inhibited by Zn(2+) and Hg(2+). The enzyme activity was regulated by feed back inhibition as it was found to be inhibited by beta-D-galactose. Chemical modification studies revealed involvement of tryptophan and histidine for enzyme activity. Involvement of tryptophan was also supported by fluorescence studies and one tryptophan was found to be present in the active site of beta-galactosidase. Circular dichroism studies revealed 37% alpha helix, 27% beta sheet and 38% random coil in the secondary structure of the purified enzyme.
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PMID:Purification of beta-galactosidase from Erythrina indica: involvement of tryptophan in active site. 1776 89

Dihydroxyacetone synthase (DHAS) is a key enzyme involved in the assimilation of methanol in Mycobacterium sp. strain JC1 DSM 3803. The structural gene encoding DHAS in Mycobacterium sp. strain JC1 was cloned using random-primed probes synthesized after PCR with synthetic primers based on the amino acid sequences conserved in two yeast DHASs and several transketolases. The cloned gene, dasS, had an ORF of 2193 nt, encoding a protein with a calculated molecular mass of 78,197 Da. The deduced amino acid sequence of dasS contained an internal sequence of Mycobacterium sp. strain JC1 DHAS and exhibited 29.2 and 27.3 % identity with those of Candida boidinii and Hansenula polymorpha enzymes, respectively. Escherichia coli transformed with the cloned gene produced a novel protein with a molecular mass of approximately 78 kDa, which cross-reacted with anti-DHAS antiserum and exhibited DHAS activity. Primer-extension analysis revealed that the transcriptional start site of the gene was the nucleotide A located 31 bp upstream from the dasS start codon. RT-PCR showed that dasS was transcribed as a monocistronic message. Northern hybridization and beta-galactosidase assay with the putative promoter region of dasS revealed that the gene was transcribed only in cells growing on methanol. The expression of dasS in Mycobacterium sp. strain JC1 was free from catabolite repression.
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PMID:Cloning, characterization and expression of a gene encoding dihydroxyacetone synthase in Mycobacterium sp. strain JC1 DSM 3803. 1804 31