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)

We have developed a ligand-specific method for the visualization, isolation, and biochemical characterization of cell surface and intracellular membranes mediating endocytic transport. Iron dextran particles (FeDex) bearing either covalently conjugated galactosyl bovine serum albumin (GalBSA/FeDex) or asialofetuin (ASF/FeDex) are bound by the asialoglycoprotein receptor (ASGP-R) of HepG2 cells and transported to lysosomes with kinetics indistinguishable from those of free GalBSA or ASF. FeDex particles, which have a 3 to 5 nm electron-dense colloidal iron core, can be visualized by electron microscopy. Following incubation of GalBSA/FeDex with HepG2 cells at 37 degrees C, FeDex particles are seen at the cell surface, in endosomes, and in lysosomes. Surface membrane and intracellular organelles bearing a sufficient number of FeDex particles can be efficiently isolated from disrupted cells by high gradient magnetic affinity chromatography (HIMAC). Plasma membranes and endosomal/lysosomal membranes isolated by HIMAC are 35 to 40-fold enriched for GalBSA/FeDex or ASF/FeDex relative to the postnuclear supernatant. Alkaline phosphodiesterase I (APDE) and galactosyltransferase are each enriched 8-fold in the plasma membrane fraction prepared by HIMAC whereas neither beta-galactosidase nor glucose-6-phosphatase are detected in this fraction. The intracellular membrane fraction, containing both endosomes and lysosomes, is enriched for galactosyltransferase and beta-galactosidase but not for APDE or glucose-6-phosphatase. Use of FeDex conjugates in conjunction with HIMAC provides an effective method for ligand-specific isolation of membranes and correlation of morphological and biochemical characteristics.
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PMID:Ligand-specific isolation of endosomes and lysosomes using superparamagnetic colloidal iron dextran glycoconjugates and high gradient magnetic affinity chromatography. 168 Jun 81

We purified a mouse DNA repair enzyme having apurinic/apyrimidinic endonuclease, DNA 3'-phosphatase, 3'-5'-exonuclease and DNA 3' repair diesterase activities, and designated the enzyme as APEX nuclease. A cDNA clone for the enzyme was isolated from a mouse spleen cDNA library using probes of degenerate oligonucleotides deduced from the N-terminal amino acid sequence of the enzyme. The complete nucleotide sequence of the cDNA (1.3 kilobases) was determined. Northern hybridization using this cDNA showed that the size of its mRNA is about 1.5 kilobases. The complete amino acid sequence for the enzyme predicted from the nucleotide sequence of the cDNA (APEX nuclease cDNA) indicates that the enzyme consists of 316 amino acids with a calculated molecular weight of 35,400. The predicted sequence contains the partial amino acid sequences determined by a protein sequencer from the purified enzyme. The coding sequence of APEX nuclease was cloned into pUC18 SmaI and HindIII sites in the control frame of the lacZ promoter. The construct was introduced into BW2001 (xth-11, nfo-2) strain cells of Escherichia coli. The transformed cells expressed a 36.4-kDa polypeptide (the 316 amino acid sequence of APEX nuclease headed by the N-terminal decapeptide of beta-galactosidase) and were less sensitive to methyl methanesulfonate than the parent cells. The fusion product showed priming activity for DNA polymerase on bleomycin-damaged DNA and acid-depurinated DNA. The deduced amino acid sequence of mouse APEX nuclease exhibits a significant homology to those of exonuclease III of E. coli and ExoA protein of Streptococcus pneumoniae and an intensive homology with that of bovine AP endonuclease 1.
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PMID:cDNA and deduced amino acid sequence of a mouse DNA repair enzyme (APEX nuclease) with significant homology to Escherichia coli exonuclease III. 193 31

Milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (Trichosurus vulpecula). Qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. However, the late-lactation milk was unusual in that the carbohydrate was mainly lactose and its concentration remained relatively high (3.5 to 5.5%). In contrast to earlier findings on the milk of the tammar wallaby (Macropus eugenii), little or no nucleotide pyrophosphatase, beta-galactosidase and alkaline phosphatase activities were detected late in lactation.
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PMID:Changes in milk carbohydrates during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia:Phalangeridae). 256 94

alpha-Lactalbumin was isolated from milk of M. eugenii and its concentration in milk samples taken at various times during lactation (0-40 weeks post partum) was determined by single radial immunodiffusion using rabbit antiserum to the purified protein. The alpha-lactalbumin concentration remained almost constant throughout lactation even though the concentration of total lactose (free lactose plus lactose contained in oligosaccharides) fell to zero after 34 weeks post partum. This fall in lactose was accompanied by a rise in the free galactose and glucose concentrations and marked increases in UDP-galactose hydrolase, nucleotide pyrophosphatase, alkaline phosphatase and acid beta-galactosidase activities. It is suggested that the in vitro hydrolysis of UDP-galactose was due to nucleotide pyrophosphatase and that this enzyme may also play a role in vivo late in lactation by making UDP-galactose unavailable for the synthesis of lactose. Alternatively, lactose and lactose-containing oligosaccharides might be degraded by the acid beta-galactosidase during or after secretion.
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PMID:Changes in alpha-lactalbumin, total lactose, UDP-galactose hydrolase and other factors in tammar wallaby (Macropus eugenii) milk during lactation. 285 90

The present study examines the role of cardiac lysosomal enzymes in the pathogenesis of the cardiomyopathy that develops in genetically diabetic C57BL/KsJ db+/db+ mice. Db+/db+ mice and littermate controls were sacrificed as age-matched pairs between 5-26 weeks of age. C57BL/6J ob/ob mice and littermates served as other controls. The hearts were excised, homogenized, and the following enzymatic activities measured: N-Acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucosaminidase, aryl sulphatase, alpha-mannosidase, alpha-glucosidase, beta-galactosidase, beta glucosidase, total p-nitrophenyl phosphatase, acid phosphatase and 5'-phosphodiesterase type IV. There is a progressive decrease in cardiac lysosomal enzyme activities of db+/db+ mice for the period 5-21 weeks of age. All enzyme activity is depressed significantly during the 9-21 week interval with beta-glucuronidase, aryl sulphatase and beta-glucosidase decreased about 40-50%. The decrease in lysosomal enzyme activity can explain the accumulation of large residual bodies and interstitial material in the myocardium of the db+/db+ animals
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PMID:Lysosomal enzymes in experimental diabetic cardiomyopathy. 678 Feb 37

The purpose of the present study was to determine the role of cardiac lysosomal enzymes in the pathogenesis of the cardiomyopathy that develops in the genetically diabetic C57BL/KsJ db+/db+ mice. Db+/db+ mice and littermate controls were sacrificed as age-matched pairs between 5 and 26 weeks of age. C57BL/6J ob/ob mice and littermates served as other controls. Following anesthesia, the hearts were excised, homogenized, and the following enzymatic activities measured: N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucosaminidase, aryl sulfatase, alpha-mannosidase, alpha-glucosidase, beta-galactosidase, beta-glucosidase, total rho-nitrophenyl phosphatase, acid phosphatase. and 5'-phosphodiesterase type IV. There is a progressive decrease in cardiac lysosomal enzyme activities of db+/db+ mice for the period 5 to 21 weeks of age. All enzyme activity is depressed significantly during the 9- to 21-week interval: alpha-glucosidase, beta-glucosidase, alpha-mannosidase, beta-galactosidase, acid phosphatase, N-acetyl-beta-galactosaminidase, 5'-phosphodiesterase type IV, and total rho-nitrophenyl phosphatase are reduced approximately 10 to 20 per cent, whereas beta-glucosaminidase, aryl sulfatase, and N-acetyl-beta-glucosaminidase are decreased almost 40 to 50 per cent. In contrast, cardiac lysosomal enzymic activity in the ob/ob mice does not differ significantly from controls aside from aryl sulfatase (20 per cent decrease) and beta-glucosidase (10 per cent decrease). This decrease in lysosomal enzyme activity can explain the accumulation of large residual bodies and interstitial material that occurs in the myocardium of the db+/db+ animals as part of the cardiomyopathy.
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PMID:Lysosomal enzymes in the heart of the genetically diabetic mouse. 742 Nov 26