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

A beta-glucosidase (EC 3.2.1.21) with a high affinity for cyclic hydroxamic acid beta-D-glucosides was purified from 48-h-old wheat (Triticum aestivum L.) seedlings. The activity occurred transiently at a high level during the non-autotrophic stage of growth, and the nature of the transient occurrence was correlated with that of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc). The glucosidase had maximum activity at an acidic pH (pH 5.5) and the purified enzyme showed a high affinity for DIMBOA-Glc, Vmax and Km being 4100 nkat/mg protein and 0.27 mM, respectively. It also hydrolyzed p-nitrophenol beta-glycosides, as well as flavone and isoflavone glucosides, but to a lesser extent. The results indicated that the primary natural substrate for the glucosidase is DIMBOA-Glc and that the enzyme is involved in defense against pathogens and herbivores in non-autotrophic wheat. The glucosidase was found to be present as oligomeric forms with a molecular mass of 260-300 kDa comprising 60- and 58-kDa monomers. The N-terminal 12-amino-acid sequences of the two monomers were identical (Gly-Thr-Pro-(Ser?)-Lys-Pro-Ala-Glu-Pro-Ile-Gly-Pro), and showed no similarity to those of other plant glucosidases. Polyacrylamide gel electrophoresis under nondenaturing condition indicated the existence of at least eight isozymes. Three cultivars of Triticum aestivum had the same zone of glucosidase activity on zymograms, but the activity zones of the Triticum species, T. aestivum L., T. spelta L. and T. turgidum L., had different mobilities.
 ...
PMID:Purification and characterization of a hydroxamic acid glucoside beta-glucosidase from wheat (Triticum aestivum L.) seedlings. 1075 Sep 1

We report the structure and expression of the Coccidioides immitis BGL2 gene which encodes a previously characterized 120-kDa glycoprotein of this fungal respiratory pathogen. The glycoprotein is recognized by immunoglobulin M tube precipitin (TP) antibody present in sera of patients with coccidioidomycosis, a reaction which has been used for serodiagnosis of early coccidioidal infection. The deduced amino acid sequence of BGL2 shows 12 potential N glycosylation sites and numerous serine-threonine-rich regions which could function as sites for O glycosylation. In addition, the protein sequence includes a domain which is characteristic of family 3 glycosyl hydrolases. Earlier biochemical studies of the purified 120-kDa TP antigen revealed that it functions as a beta-glucosidase (EC 3.2.1.21). Its amino acid sequence shows high homology to several other reported fungal beta-glucosidases which are members of the family 3 glycosyl hydrolases. Results of previous studies have also suggested that the 120-kDa beta-glucosidase participates in wall modification during differentiation of the parasitic cells (spherules) of C. immitis. In this study we showed that expression of the BGL2 gene is elevated during isotropic growth of spherules and the peak of wall-associated BGL2 enzyme activity correlates with this same phase of parasitic cell differentiation. These data support our hypothesis that the 120-kDa beta-glucosidase plays a morphogenetic role in the parasitic cycle of C. immitis.
 ...
PMID:Cloning and expression of the gene which encodes a tube precipitin antigen and wall-associated beta-glucosidase of Coccidioides immitis. 1125 76

Recently, we identified the maize beta-glucosidase aggregating factor (BGAF) as a jacalin-related lectin (JRL) and showed that its lectin domain is responsible for beta-glucosidase aggregation. By searching for BGAF homologs in sorghum, we identified and obtained an EST clone and determined its complete sequence. The predicted protein had the same modular structure as maize BGAF, shared 67% sequence identity with it, and revealed the presence of two potential carbohydrate-binding sites (GG...ATYLQ, site I and GG...GVVLD, site II). Maize BGAF1 is the only lectin from a class of modular JRLs containing an N-terminal dirigent and a C-terminal JRL domain, whose sugar specificity and beta-glucosidase aggregating activity have been studied in detail. We purified to homogeneity a BGAF homolog designated as SL (Sorghum lectin) from sorghum and expressed its recombinant version in Escherichia coli. The native protein had a molecular mass of 32 kD and was monomeric. Both native and recombinant SL-agglutinated rabbit erythrocytes, and inhibition assays indicated that SL is a GalNAc-specific lectin. Exchanging the GG...GVVLD motif in SL with that of maize BGAF1 (GG...GIAVT) had no effect on GalNAc-binding, whereas binding to Man was abolished. Substitution of Thr(293) and Gln(296) in site I to corresponding residues (Val(294) and Asp(297)) of maize BGAF1 resulted in the loss of GalNAc-binding, indicating that site I is responsible for generating GalNAc specificity in SL. Gel-shift and pull-down assays after incubating SL with maize and sorghum beta-glucosidases showed no evidence of interaction nor were any SL-protein complexes detected in sorghum tissue extracts, suggesting that the sorghum homolog does not participate in protein-protein interactions.
 ...
PMID:Homolog of the maize beta-glucosidase aggregating factor from sorghum is a jacalin-related GalNAc-specific lectin but lacks protein aggregating activity. 1905 85

Soybean hulls were evaluated as a resource for production of ethanol by the simultaneous saccharification and fermentation (SSF) process, and no pretreatment of the hulls was found to be needed to realize high ethanol yields with Saccharomyces cerevisiae D(5)A. The impact of cellulase, beta-glucosidase and pectinase dosages were determined at a 15% biomass loading, and ethanol concentrations of 25-30 g/L were routinely obtained, while under these conditions corn stover, wheat straw, and switchgrass produced 3-4 times lower ethanol yields. Removal of carbohydrates also concentrated the hull protein to over 25% w/w from the original roughly 10%. Analysis of the soybean hulls before and after fermentation showed similar amino acid profiles including an increase in the essential amino acids lysine and threonine in the residues. Thus, eliminating pretreatment should assure that the protein in the hulls is preserved, and conversion of the carbohydrates to ethanol with high yields produces a more concentrated and valuable co-product in addition to ethanol. The resulting upgraded feed product from soybean hulls would likely to be acceptable to monogastric as well as bovine livestock.
 ...
PMID:Fermentation of soybean hulls to ethanol while preserving protein value. 1932 81

Beta-glucosidases (Glu1 and Glu2) in maize specifically interact with a lectin called beta-glucosidase aggregating factor (BGAF). We have shown that the N-terminal (Glu(50)-Val(145)) and the C-terminal (Phe(466)-Ala(512)) regions of maize Glu1 are involved in binding to BGAF. Sequence comparison between sorghum beta-glucosidases (dhurrinases, which do not bind to BGAF) and maize beta-glucosidases, and the 3D-structure of Glu1 suggested that the BGAF-binding site on Glu1 is much smaller than predicted previously. To define more precisely the BGAF-binding site, we constructed additional chimeric beta-glucosidases. The results showed that a region spanning 11 amino acids (Ile(72)-Thr(82)) on Glu1 is essential and sufficient for BGAF binding, whereas the extreme N-terminal region Ser(1)-Thr(29), together with C-terminal region Phe(466)-Ala(512), affects the size of Glu1-BGAF complexes. The dissociation constants (K(d)) of chimeric beta-glucosidase-BGAF interactions also demonstrated that the extreme N-terminal and C-terminal regions are important but not essential for binding. To confirm the importance of Ile(72)-Thr(82) on Glu1 for BGAF binding, we constructed a chimeric sorghum beta-glucosidase, Dhr2 (C-11, Dhr2 whose Val(72)-Glu(82) region was replaced with the Ile(72)-Thr(82) region of Glu1). C-11 binds to BGAF, indicating that the Ile(72)-Thr(82) region is indeed a major interaction site on Glu1 involved in BGAF binding.
 ...
PMID:Determination of beta-glucosidase aggregating factor (BGAF) binding and polymerization regions on the maize beta-glucosidase isozyme Glu1. 1971 49


<< Previous 1 2