Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously identified and purified a novel beta-glucosidase, designated PNGH (pyridoxine-5'-beta-D-glucoside hydrolase), from the cytosolic fraction of pig intestinal mucosal. PNGH catalyses the hydrolysis of PNG (pyridoxine-5'-beta-D-glucoside), a plant derivative of vitamin B6 that exhibits partial nutritional bioavailability in humans and animals. Preliminary amino acid sequence analysis indicated regions of close similarity of PNGH to the precursor form of LPH (lactase-phlorizin hydrolase), the beta-glucosidase localized to the brush-border membrane. We report in the present study amino acid sequence data for PNGH and results of Northern blot analyses, upon which we propose a common genomic origin of PNGH and LPH. Internal Edman sequencing of the PNGH band isolated by SDS/PAGE yielded data for 16 peptides, averaging 10.8 amino acids in length. These peptides from PNGH (approx. 140 kDa) were highly similar to sequences existing over most of the length of the >200 kDa precursor of rabbit LPH; however, we found no PNGH sequences that corresponded to approx. 350 amino acids between positions 463 and 812 of the LPH precursor, a region encoded by exon 7 of the LPH precursor gene (amino acids 568-784), and no sequences that corresponded to regions near the N-terminus. MS analysis of tryptic peptides yielded 25 peptides, averaging 15 amino acids, with masses that matched segments of the rabbit LPH precursor. Northern blot analysis of pig and human small intestinal polyadenylated mRNA using a non-specific LPH cDNA probe showed an expected approx. 6 kb transcript of the LPH precursor, but also an approx. 4 kb transcript that was consistent with the size predicted from the PNGH protein mass. Using a probe specific to the region encoded by exon 7, hybridization occurred only with the 6 kb transcript. Based on these observations, we propose that both PNGH and LPH enzymes have the same genomic origin, but differ in transcriptional and, possibly, post-translational processing.
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PMID:Partial amino acid sequence and mRNA analysis of cytosolic pyridoxine-beta-D-glucoside hydrolase from porcine intestinal mucosa: proposed derivation from the lactase-phlorizin hydrolase gene. 1497 28

Bacterial degradation of mucilaginous aggregates (creamy layers, stringers and macroflocs) collected during two summer events (2001-2002) was tested. The objective was to describe the temporal trend of the bacterial activity, abundance and composition in the aggregated and dissolved organic matter under different trophic conditions. In the native aggregates proteins and organic phosphorous were actively hydrolyzed as aminopeptidase and alkaline phosphatase activities represented up to 87% and 25% of total activity, respectively; polysaccharides were less hydrolyzed and the highest activities were observed for beta-glucosidase (5% of the total). This hydrolysation pattern tends to a progressive accumulation of long persistent polysaccharides. During short term incubations nutrient addition (P, N and Glucose) differently stimulated bacterial growth in the seawater: P played the main role in stimulating bacterial production from 3 to 6 folds higher than in the control, whereas a secondary C-limitation was observed only for bacteria growing on seawater from macroflocs. This scarce dissolved organic carbon (DOC) bioavailability was confirmed by the lower DOC removal (13% macroflocs, 36% stringers). The total amount of carbon incorporated by bacteria living on aggregates was similar (0.58 mg C L(-1)) both in the control and under P enrichments showing a more balanced condition with respect to the seawater. Hence the well-known P limitation in the Northern Adriatic Sea affects only dissolved organic carbon uptake without influencing the uptake of aggregated organic matter. Organic matter limitation was observed only on stringers--total C incorporated raised to 0.96 mg C L(-1) after PNG addition. Macroflocs release of refractory compounds leads to DOC accumulation (73 microM DOC) contributing to inflate the pool of refractory DOC in the surrounding waters. Several evidences, including different monosaccharide composition of stringers and macroflocs (glucose 15% and 56% on stringers and macroflocs, respectively), bring to the conclusion that stringers are in an older stage in comparison with macroflocs. Community composition described by fluorescence in situ hybridization did not show significant differences between free-living and attached bacteria but it was modified by the different enrichment conditions: Cytophaga-Flavobacteria increased after inorganic nutrients enrichments while organics advantaged gamma-Proteobacteria.
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PMID:Extracellular enzyme activity and dynamics of bacterial community in mucilaginous aggregates of the northern Adriatic Sea. 1631 Aug 35