Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One acid alpha-glucosidase and two neutral alpha-glucosidases were separated from human skeletal muscle by DEAE-cellulose column chromatography. The appearance of the two human neutral alpha-glucosidase isoenzymes was found to be age dependent. We called them "fetal" and "adult" neutral alpha-glucosidases. The biochemical properties of the fetal and adult types of neutral alpha-glucosidases appeared to be similar to those previously reported for neutral alpha-glucosidases AB and C, respectively. The neutral alpha-glucosidase activity in the column eluate of the infantile acid maltase deficiency (AMD; 5-month-old) muscle was completely of the adult type, whereas 18% of the total neutral alpha-glucosidase activity in age-matched control muscle was of the fetal type. In contrast, the eluate of the late-onset AMD (32-year-old) muscle contained both the adult and fetal neutral alpha-glucosidases, 68 and 32%, respectively.
 ...
PMID:alpha-Glucosidase isoenzymes in normal and acid maltase-deficient human skeletal muscles. 313 93

1. The intestinal disaccharidase activities of a suckling crabeater seal were investigated. 2. Lactase, maltase, isomaltase and cellobiase activities were readily detected but trehalase and sucrase activities were absent. 3. The intestinal homogenates were separated into a soluble (S2) fraction and a particulate brush border (P2) fraction. The lactase activities of the two fractions had different properties corresponding to those of an acid and a neutral beta-galactosidase respectively. Approximately two-thirds of the total lactase activity measured at pH 6.0 was due to the acid beta-galactosidase. 4. The isomaltase and cellobiase activities were found almost exclusively in the particulate fractions but about one third of the maltase activity was in the S2 fraction. This soluble maltase activity appeared to be due to an acid maltase.
 ...
PMID:Intestinal lactase and other disaccharidase activities of a suckling crabeater seal (Lobodon carcinophagus). 313 70

A male patient is reported with a mutation of acid alpha-glucosidase causing an altered Km toward natural substrates. Cardiac arrhythmia was found at 12 years of age, and he died of heart failure at 15 years. No skeletal muscle involvement was observed either clinically or histologically. Acid alpha-glucosidase activity in fibroblasts was moderately low (43% of the control mean) with normal Km for 4-methylumbelliferyl alpha-D-glucoside. The hydrolysis of glycogen was markedly decreased (14% of the control mean), and the Km for maltose was increased 4-fold and for glycogen 5-fold. The biosynthesis and the posttranslational processing of the mutant enzyme appeared normal, but the total amount of the enzyme was lower than normal. This mutant enzyme comigrated with normal acid alpha-glucosidase on starch gel electrophoresis, and not with the rare isozyme, acid alpha-glucosidase 2. A possible role of this mutant enzyme in the pathogenesis of this disease and the relationship to glycogenesis II are discussed.
 ...
PMID:Km mutant of acid alpha-glucosidase in a case of cardiomyopathy without signs of skeletal muscle involvement. 328 78

A specific assay for acid alpha-glucosidase in urine was developed to facilitate the diagnosis of glycogenosis II. This enzyme activity was calculated as a difference between the alpha-glucosidase activities before and after immunoprecipitation with antiserum to acid alpha-glucosidase. Acid alpha-glucosidase accounted for 86% of the total activity in control urine. All the cases of various clinical types of glycogenosis II showed either a marked decrease or a complete deficiency of this enzyme activity. A marked decrease of acid alpha-glucosidase was demonstrated by immunoblotting of the urine from patients with late-onset forms of this disease. These results indicate that assays of urinary acid alpha-glucosidase by this immunological method are useful for detection of the various types of glycogenosis II.
 ...
PMID:A simple differential immunoprecipitation assay of urinary acid and neutral alpha-glucosidases for glycogenosis II. 330 22

We have defined one type of acid alpha-glucosidase and two types of neutral alpha-glucosidases from quail skeletal muscle on the basis of differences in the elution patterns on a DEAE-cellulose column. The appearance of the two neutral alpha-glucosidase isoenzymes was age-dependent. A decrease in acid alpha-glucosidase activity was demonstrated in Japanese quails with glycogenosis type II. The characteristics of these three alpha-glucosidase isoenzymes are described.
 ...
PMID:Isolation and characterization of three alpha-glucosidases from the Japanese quail. 351 97

An asialoglycoprotein receptor was isolated from murine liver and purified more than 1600-fold using 2-fold affinity chromatography on asialoorosomucoid-Sepharose. The purified receptor did not interact with 125I-orosomucoid, but bound to 125I-asialoorosomucoid. The binding of the receptor to asialoorosomucoid was saturable. The dissociation constant of the receptor-asialoorosomucoid complex was 0.4 X 10(-9) M. The molecular mass of the receptor, as determined with the use of specific antibodies by the immunoblotting method, was 43 kDa. High concentrations of unlabeled asialoorosomucoid and of n-aminophenyl-beta-D-galactosyl derivatives of bovine serum albumin, ovalbumin and acid alpha-glucosidase from human liver inhibited the binding of the receptor to 125I-asialoorosomucoid almost completely. The binding of the receptor to 125I-galactolyzed alpha-glucosidase was pH-dependent, with the pH optimum at 8.0-9.0. It was shown that, as in the case of 125I-asialoorosomucoid, the binding of the 125I-galactosyl derivative of alpha-glucosidase occurred in the presence of Ca2+ and was inhibited by N-acetylgalactosamine. Glycoproteins containing galactose as a terminal residue inhibited the interaction of the receptor with 125I-galactolyzed alpha-glucosidase. The possibility of directed transport of the galactolyzed alpha-glucosidase derivative into parenchymous liver cells using receptor-mediated endocytosis is discussed.
 ...
PMID:Interaction of hepatic asialoglycoprotein receptor with asialoorosomucoid and galactolyzed lysosomal alpha-glucosidase. 352 76

The role of lysosomal enzyme acid alpha-glucosidase in fetal lung development was investigated with the aid of a specific inhibitor, the pseudosaccharide acarbose. The drug was added to a Waymouth culture medium of fetal rat lung explants cultivated for 48 h from gestational stage 19.5 days, an in vitro system previously shown to allow morphological and biochemical maturation of alveolar epithelium. Glycogenolysis was reduced by 40% as compared with tissue cultivated on control medium, which means that alpha-glucosidase could account for as much as 40% of fetal lung glycogenolysis, the remaining 60% being presumably achieved by cytosolic phosphorylase and by a microsomal neutral alpha-glucosidase. By the same time, the increase of phospholipids of surfactant fraction extracted from cultivated explants was partially inhibited: total and saturated phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol were about 30-40% lower than in lungs cultivated on control medium. It should be emphasized that DNA concentration and increases in non-surfactant phospholipids were unchanged by the drug. alpha-Glucosidase activity was evidenced in the lysosomal fraction, in the microsomal fraction and, although in lower amounts, in the surfactant fraction extracted from term fetal lung. The results suggest that lysosomal alpha-glucosidase plays a major role in lung maturation and could facilitate glycogenolysis for the specific use of glycogen stores in providing substrates for surfactant phospholipid biosynthesis.
 ...
PMID:Role of alpha-glucosidase in fetal lung maturation. 353 7

We have recently shown that lamellar body fractions purified from human lung contain a distinct acid alpha-glucosidase distinguishable from lysosomal acid alpha-glucosidase in that it does not cross-react with antibodies raised against the lysosomal enzyme and does not bind to concanavalin A (De Vries, A.C.J., Schram, A.W., Tager, J.M., Batenburg, J.J. and Van Golde, L.M.G. (1985) Biochim. Biophys. Acta 837, 230-238). In order to study the relationship between the non-concanavalin A-binding alpha-glucosidase and lamellar bodies more closely a method was developed for the further purification of the organelles. A purified lamellar body preparation isolated from human lung homogenate by discontinuous sucrose density centrifugation was subjected to gel filtration with Sepharose 4B followed by Percoll density gradient centrifugation, which yielded a lamellar body preparation with a phospholipid phosphorus/protein ratio of 12.57 +/- 0.38 (mumol/mg) (n = 3) as compared to a ratio of 3.34 +/- 0.16 (mumol/mg) (n = 3) in the sucrose density gradient preparation. Concomitantly there was a 3.3 +/- 0.1 (n = 3)-fold enrichment in the content of total acid alpha-glucosidase and a 3.2 +/- 0.1 (n = 3) -fold enrichment of non-concanavalin A-binding acid alpha-glucosidase. The new purification method removes adhering proteins without changing the phospholipid composition. During the successive purification steps the concanavalin A-sensitive and -insensitive alpha-glucosidases remained fully lamellar body fraction associated. Differences between a lysosome-enriched fraction and a lamellar body preparation at varying stages of purification with respect to the ratio between soluble acid hydrolases and the membrane-associated lysosomal enzyme glucocerebrosidase indicate that the purified lamellar bodies were not contaminated with lysosomes. The absence of lysosomes in the purified lamellar body fraction was confirmed by experiments with the weak base glycyl-L-phenylalanine-beta-naphthylamide, which is an artificial substrate for the lysosomal enzyme cathepsin C and brings about lysis of lysosomes. Morphological examination by electron microscopy endorses the absence of contaminating vesicles and organelles and showed a structural integrity of the lamellar bodies in the final preparation. The improved isolation procedure strongly suggests that the concanavalin A-insensitive acid alpha-glucosidase is endogenous to lamellar bodies and supports our earlier idea that it can be used as a lamellar body-specific marker enzyme. In addition, the experiments show that lamellar bodies free of lysosomes contain a spectrum of lysosomal-type enzymes.
 ...
PMID:An improved procedure for the isolation of lamellar bodies from human lung. Lamellar bodies free of lysosomes contain a spectrum of lysosomal-type hydrolases. 368 11

Kinetic and immunological studies of 1,4-alpha-glucosidase show that the distribution of acid, renal and neutral alpha-glucosidase at pH 4.0 and 6.5 is as follows: in liver and cultured fibroblasts and amniotic fluid cells the activity at pH 4.0 is mainly due to the acid enzyme. Even at pH 6.5, the activity is largely due to the residual activity of the acid enzyme. In kidney and leukocytes, however, the activity by acid enzyme at pH 4.0 represents only 30-60% of the total activity and the remaining activity is from renal enzyme. At pH 6.5, the activity is almost exclusively of renal enzyme. Renal alpha-glucosidase has a higher affinity for maltose (Km, 0.8 mmol/l) than acid enzyme, however; for glycogen acid enzyme shows the highest affinity (20.7 g/l). There is no significant difference in the kinetic characteristics of alpha-glucosidase between fetal and adult tissues. In kidney, however, a relative increase in renal enzyme to acid enzyme with age is found, i.e. in fetal kidney the alpha-glucosidase activity at pH 4.0 is more than twice that at pH 6.5, whereas in adult kidney, the activity ratio at pH 4.0-6.5 is approximately 1. Antibodies for human liver acid alpha-glucosidase decrease the alpha-glucosidase activity in normal leukocytes by 22-75% at pH 4.0 (0.54-3.8 nmol/min per mg protein). The decrease is significantly lower in patients with Pompe's disease (0-0.11 nmol/min per mg protein) as well as in their parents and some siblings (0.15-0.70).
 ...
PMID:Diagnosis of Pompe's disease using leukocyte preparations. Kinetic and immunological studies of 1,4-alpha-glucosidase in human fetal and adult tissues and cultured cells. 389 Nov 51

Acid alpha-glucosidase and L-carnitine (a well-known epididymal marker) were measured in rete testis and epididymal fluids of adult male rams. These fluids were collected by selective catheterization or by a micropuncture technique, respectively. Both parameters remained at a low and constant level in rete testis and all along caput and corpus epididymidis. Then they increased at equivalent rates in cauda epididymidis to much higher levels than those in seminal plasma (5 mU/mg protein and 10 mM, respectively). An optimum pH study of alpha-glucosidase activity in these fluids showed two well-separated peaks in rete testis and caput epididymal fluids around pH 4 and 7, respectively, but only a single peak at pH 4 in cauda epididymidis that was comparable to the one in seminal plasma. Sucrose density gradient fractions analyzed for their enzyme content in the absence or presence of sodium dodecyl sulfate (1% w/v), a selective inhibitor of acid alpha-glucosidase activity, allowed the demonstration of two enzyme forms at pH 6.8 in rete testis fluid sedimenting in the 7S and 4S regions of the gradient, while a unique 4S form was encountered in cauda epididymidis and in seminal plasma. Although the fate of the minor 7S component of the rete testis fluid in its epididymal transit is presently unknown, similarities between the enzyme in cauda epididymidis and seminal plasma are strong enough to support the hypothesis that epididymis contributes primarily to the acid alpha-glucosidase content of ram seminal plasma.
 ...
PMID:Major contribution of epididymis to alpha-glucosidase content of ram seminal plasma. 389


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>