Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alterations in the cardiac tissue and serum acid hydrolase activities were studied in chronic streptozotocin-induced diabetes in rats. No changes were observed in total cardiac tissue homogenate lysosomal enzyme activities at 4 weeks of diabetes but there were significant alterations in the distribution of selected enzymes. Significant decreases in nonsedimentable beta-N-acetylglucosaminidase (NAG) and beta-galactosidase (Gal) activities were observed at 4 weeks of diabetes. At 8 weeks of the disease, decreased activities of NAG and Gal were observed in heart homogenates but no changes were apparent in alpha-mannosidase (Man) or acid phosphatase activities. Nonsedimentable activities of NAG and both sedimentable and nonsedimentable activities of Gal were decreased at 8 weeks. At 16 weeks of the diabetic condition, increased activities of NAG, Gal and acid phosphatase were observed. This increase at 16 weeks of the disease was due to an increase in sedimentable enzyme activity. At all times of diabetes, serum enzyme activities were significantly increased. Insulin treatment reversed all of the observed changes in tissue homogenates, but serum levels were not completely reversed. These results suggest that cardiac lysosomal hydrolases are probably only involved in the later stages of the diabetic cardiomyopathy when extensive ultrastructural derangements are evident. The present evidence also suggests that the heart may be a source of serum hydrolase activities.
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PMID:Alterations in heart and serum lysosomal activities in streptozotocin-induced diabetes. 295 2

A modified procedure has been worked out for preparing a conjugate of porcine insulin with E. coli beta-galactosidase employing a heterobifunctional reagent, N-hydroxysuccinimidyl m-maleimidobenzoate. Optimal conditions for insulin acylation and subsequent coupling with beta-galactosidase were selected that afforded the conjugate in a high yield. The ability of the modified antigen to react with antibody was evaluated in the reaction of conjugate binding with immobilized monoclonal antibody to insulin. The conjugate almost completely retained the enzymatic activity and reacted with high specificity with the antibody to insulin. The conjugate can be used in competitive ELISA of insulin.
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PMID:[Preparation of an insulin conjugate with beta-galactosidase from E. coli for immunoenzyme assay]. 308 25

The effect of streptozotocin (SZ) on the development of small intestinal enzymes in postnatal rat pups was studied. SZ was injected ip on Day 10 and, if necessary, again on Day 12. On Days 15, 18, and 21, one pup from each group (including a vehicle-injected control (C) group) was decapitated under conditions which minimized stress. Plasma glucose, insulin (IRI), and corticosterone were measured, as were pancreatic IRI, liver glycogen, and liver membrane binding of IRI. Small intestinal segments were processed and analyzed for sucrase, lactase, maltase, and ileal acid beta-galactosidase activities. Our results indicate that plasma glucocorticoid levels remained virtually constant in both SZ and C groups, while the ontogenic profiles of sucrase and maltase in SZ rats were shifted toward an earlier appearance and a precocious maturation. Circulating levels of IRI were not reduced significantly by SZ despite the fact that pancreatic IRI was decreased 95%. Jejunal lactase, unlike data reported for diabetic rats, was not affected by SZ diabetes. Also, acid beta-galactosidase was unaltered in the SZ rat pups. It is concluded that possibly the elevated disaccharidases seen in diabetic postnatal rat pups are the direct effect of elevated blood glucose. If so, the SZ rat pup model may be a useful tool with which to study effects of glucose on intestinal enzymes in the absence of changes in plasma insulin.
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PMID:Effects of diabetes on development of small intestinal enzymes of infant rats. 312 20

We recently reported marked differences in insulin binding properties in Chinese hamster ovarian cell mutants with genetic defects in protein N-glycosylation. To further characterize the role of insulin receptor carbohydrates, we have now studied the effect of lectins on [125I]insulin binding to wild type (WT) Chinese hamster ovarian cells and to two mutant cell lines: B4-2-1, to which insulin was previously shown to bind with higher affinity than normal, and Lec 1, to which insulin binds with much lower affinity. The results show that of four lectins that bound to WT cells; only wheat germ agglutinin and phytohemagglutinin-E competed with insulin binding to these cells, while Concanavalin A (ConA) and Erythrina cristagalli agglutinin (ECA) did not. After solubilization of the cells, however, a potent inhibition of insulin binding was also seen with ConA and ECA. This suggests that sugar determinants for ConA and ECA are present on the insulin receptor, but are not accessible at the surface of the cells. Mutant B4-2-1 cells, which are deficient in mannosylphosphoryldolichol synthase and beta-galactosidase, differed from WT cells in that ECA and ConA potently inhibited insulin binding in intact cells. This suggests that these lectin binding sites of or near the insulin receptor are more accessible at the cell surface in this mutant cell line. Mutant Lec 1 cells, deficient in N-acetylglucosaminyl-transferase I, cannot process N-linked carbohydrates from their oligomannose to their complex forms. In these cells, marked differences in the pattern of lectin inhibition were observed compared to that in WT or B4-2-1 cells. ConA exerted a strong inhibition of insulin binding to solubilized cell preparations. Its effect on intact cells was modest however, suggesting that in this mutant line exposure of the insulin receptor at the cell surface is not different from that in the WT cells. Neither ECA nor PHA inhibited [125I]insulin binding to either intact or solubilized Lec 1 cells, suggesting that the absence of sugar determinants for these two lectins may play a role in the very low insulin binding affinity previously reported in this cell line. In conclusion, these indirect studies with lectins suggest that the carbohydrate units of the insulin receptor are heterogeneous. While some may be important for proper exposure of the receptor at the cell surface, others may play a role in more intrinsic receptor properties.
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PMID:Lectins as probes of insulin receptor carbohydrate composition: studies in glycosylation mutants of Chinese hamster ovarian cells with altered insulin binding. 351 53

The alpha-complementation reaction was adapted as a quantitative assay for fusion proteins consisting of the B chain of human insulin fused to the C terminus of the truncated beta-galactosidase.
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PMID:A quantitative beta-galactosidase alpha-complementation assay for fusion proteins containing human insulin B-chain peptides. 609 27

Described is a novel method of fabrication of crystallized carbohydrate spheres with entrapped substances where it is shown that entrapped peptide hormones such as insulin and interferon, enzymes such as plasmin and beta-galactosidase and monoclonal antibodies retain their biological activity after release from the matrix. In vitro slow release of proteins over several weeks is achieved by erosion of the matrix consisting of carbohydrate polymers such as dextran, dextrins or low molecular weight carbohydrates such as glucose and maltose, all well known biodegradable and biocompatible matrix materials.
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PMID:Crystallized carbohydrate spheres as a slow release matrix for biologically active substances. 620 33

As an approach to the study of mammalian gene expression, the promoters and translation initiation regions of the rat preproinsulin II and the simian virus 40 early genes were fused to the structural gene of Escherichia coli beta-galactosidase, a sensitive probe for gene expression. These fusions were introduced into COS-7 cells, a simian virus 40 large tumor-antigen-producing monkey kidney cell line, where they directed the synthesis of enzymatically active hybrid beta-galactosidase proteins. Conditions for transfection were varied to optimize the expression of beta-galactosidase activity in the transfected cells. The pH optimum of this activity was found to be 7.0, the same as that of native E. coli beta-galactosidase and distinct from the major lysosomal "acid" beta-galactosidase. The fused preproinsulin-beta-galactosidase was further characterized by gel electrophoresis of nondenatured cell extracts stained by a fluorogenic substrate and by immunoprecipitation and gel electrophoresis of 3H-labeled cell proteins. These results all indicate that fully active tetrameric beta-galactosidase hybrids can be produced in mammalian cells. The expression of preproinsulin-beta-galactosidase activity was measured in the presence of high glucose, insulin, dexamethasone, or epidermal growth factor but no regulatory changes were observed.
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PMID:Expression of a preproinsulin-beta-galactosidase gene fusion in mammalian cells. 631 May 64

A new cytoplasmic endoprotease, named protease So, was purified to homogeneity from Escherichia coli by conventional procedures with casein as the substrate. Its molecular weight was 140,000 when determined by gel filtration on Sephadex G-200 and 77,000 when estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Thus, it appears to be composed of two identical subunits. Protease So had an isoelectric point of 6.4 and a K(m) of 1.4 muM for casein. In addition to casein, it hydrolyzed globin, glucagon, and denatured bovine serum albumin to acid-soluble peptides but did not degrade insulin, native bovine serum albumin, or the "auto alpha" fragment of beta-galactosidase. A variety of commonly used peptide substrates for endoproteases were not hydrolyzed by protease So. It had a broad pH optimum of 6.5 to 8.0. This enzyme is a serine protease, since it was inhibited by diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride. Although it was not inhibited by chelating agents, divalent cations (e.g., Mg(2+)) stabilized its activity. Protease So was sensitive to inhibition by N-tosyl-l-phenylalanine chloromethyl ketone but not by N-tosyl-l-lysine chloromethyl ketone. Neither ATP nor 5'-diphosphate-guanosine-3'-diphosphate affected the rate of casein hydrolysis. Protease So was distinct from the other soluble endoproteases in E. coli (including proteases Do, Re, Mi, Fa, La, Ci, and Pi) in its physical and chemical properties and also differed from the membrane-associated proteases, protease IV and V, and from two amino acid esterases, originally named protease I and II. The physiological function of protease So is presently unknown.
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PMID:Purification and characterization of protease So, a cytoplasmic serine protease in Escherichia coli. 633 74

We have developed an enzyme-linked immunosorbent assay (ELISA) for the detection and quantitation of islet antibodies (ICA) in sera from insulin-dependent diabetic (IDD) subjects or from Bio-Breeding/Worcester (BB/W) rats. Whole rat or mouse islet cells, either glutaraldehyde-fixed or desiccated, which can be stored and used over a long period, were used as antigens. The amount of antibody bound to the cells is quantitated by the addition of sheep anti-human or anti-rat IgG conjugated with beta-galactosidase. This quantitative ELISA compared favourably with other assays for ICA detection.
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PMID:Enzyme-linked immunosorbent assay for quantitation of islet cell antibodies. 635 62

The catalytic activities of N-acetyl-beta-D-glucosaminidase, beta-galactosidase and alpha-glucosidase in kidney and urine of diabetic rats were investigated in relation to the duration of diabetes, to the degree of constant hyperglycaemia and to the therapeutic control in the early stage of disease. The results suggest that the degree of constant hyperglycaemia and the duration of untreated diabetes are significant determining factors for the course of morphological changes. These changes are manifested as a decrease of the glycosidases in kidney (0.5 to 0.6 time the age-matched controls) and as moderate to severe enzymurias. Daily variation of blood glucose with inadequate insulin Lente therapy caused decreased N-acetyl-beta-D-glucosaminidase and beta-galactosidase activities in kidney as well as enzymuria. Since such changes can be correlated with histologically visible changes in the kidney, the measurement of these enzymes in urine is a simple way of monitoring the development of kidney damage in poorly controlled diabetes. When constant normoglycaemia was maintained for three weeks with insulin Ultralente in diabetic rats with a confirmed decrease of kidney glycosidases, the persisting morphological alteration of the organ was reflected by a urinary output of N-acetyl-beta-D-glucosaminidase.
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PMID:Effect of the degree of hyperglycaemia on the catalytic activities of glycosidases in kidney and urine of diabetic rats. 636 9


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