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)

Stable-isotopic methods were employed to evaluate the utilization of dietary pyridoxine-5'-beta-D-glucoside (PN-glucoside), a major form of vitamin B-6 in plant-derived foods, as a source of available vitamin B-6 for adult men (20-35 y old, n = 5). Deuterium-labeled forms of free pyridoxine (PN) and PN-glucoside were compared using the urinary excretion of labeled forms of the vitamin B-6 metabolite 4-pyridoxic acid as the main index of absorption and metabolism. When comparing orally administered, isotopically labeled PN and PN-glucoside in separate groups of subjects, similar bioavailability was observed although within-group variability was high. A dual-label study designed to examine the bioavailability of these compounds when administered simultaneously indicated that the utilization of deuterated PN-glucoside was 58 +/- 13% (mean +/- SEM) relative to that of deuterated PN. PN-glucoside was detected in all urine samples, which provided additional evidence of incomplete metabolic utilization. In contrast, intravenously administered PN-glucoside underwent approximately half the metabolic utilization of oral PN-glucoside. These studies indicate that the bioavailability of dietary PN-glucoside, although incomplete, is substantially greater in humans than previously found in rats. In addition, the difference between oral and intravenous routes suggests a role of beta-glucosidase(s) of the intestinal mucosa, microflora, or both in the release of free PN from dietary PN-glucoside.
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PMID:Bioavailability of pyridoxine-5'-beta-D-glucoside determined in humans by stable-isotopic methods. 199 88

Visible browning is a typical feature of callus cultures derived from shoot tips of mature Scots pine (Pinus sylvestris L.). Because the ability of callus to regenerate is low, we determined the effect of browning on growth and changes in cellular structure during culture. Striking alterations in cellular structure were detected by LM (light microscopy), EM (electron microscopy) and SEM (scanning electron microscopy). Accumulation of phenolic substances was shown by histochemical staining. Staining for beta-glucosidase activity of soluble proteins that had been subjected to polyacrylamide gel electrophoresis indicated lignification of cells. The measured growth rate of callus was low compared with a hypothetical growth curve. Peroxidase activity increased rapidly soon after the start of the culture period, but especially between the second and third weeks of culture. At this time, the degradation of cell membranes and browning began coincident with the loss of chlorophyll. We conclude that browning is associated with cell disorganization and eventual cell death, making tissue culture of mature pine especially difficult.
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PMID:Changes in cellular structures and enzymatic activities during browning of Scots pine callus derived from mature buds. 1265 42

Rice straw was irradiated using an electron beam at currents and then hydrolyzed with cellulase and beta-glucosidase to produce glucose. The pretreatment by electron beam irradiation (EBI) was found to significantly increase the enzyme digestibility of rice straw. Specifically, when rice straw that was pretreated by EBI at 80 kGy at 0.12 mA and 1 MeV was hydrolyzed with 60 FPU of cellulase and 30 CBU of beta-glucosidase, the glucose yield after 132 h of hydrolysis was 52.1% of theoretical maximum. This value was significantly higher than the 22.6% that was obtained when untreated rice straw was used. In addition, SEM analysis of pretreated rice straw revealed that EBI caused apparent damage to the surface of the rice straw. Furthermore, EBI pretreatment was found to increase the crystalline portion of the rice straw. Finally, the crystallinity and enzyme digestibility were found to be strongly correlated between rice straw samples that were pretreated by EBI under different conditions.
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PMID:Improved enzymatic hydrolysis yield of rice straw using electron beam irradiation pretreatment. 1893 Mar 88

Corn stover was pretreated with FeCl(3) to remove almost all of the hemicellulose present and then hydrolyzed with cellulase and beta-glucosidase to produce glucose. Enzymatic hydrolysis of corn stover that had been pretreated with FeCl(3) at 160 degrees C for 20 min resulted in an optimum yield of 98.0%. This yield was significantly higher than that of untreated corn stover (22.8%). FeCl(3) pretreatment apparently damaged the surface of corn stover and significantly increased the enzymatic digestibility, as evidenced by SEM and XRD analysis data. FTIR analysis indicated that FeCl(3) pretreatment could disrupt almost all the ether linkages and some ester linkages between lignin and carbohydrates but had no effect on delignification. The FeCl(3) pretreatment technique, as a novel pretreatment method, enhances enzymatic hydrolysis of lignocellulosic biomass by destructing chemical composition and altering structural features.
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PMID:Enhanced enzymatic hydrolysis and structural features of corn stover by FeCl3 pretreatment. 1958 Oct 85