Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Portions of closed jejunal biopsies from the dog were homogenised and their organelles separated by isopycnic centrifugation on continuous sucrose density gradients. The distributions of marker enzymes for the principal organelles were determined using highly sensitive assay procedures. The following organelles, with assayed marker enzymes and modal densities between brackets were characterised: peroxisomes (catalase, 1.21); brush borders (zinc-resistant alpha-glucosidase, leucyl-beta-naphthyl-amidase, gamma-glutamyl transferase, alkaline phosphatase, 1.20); lysosomes (N-acetyl-beta-glucosaminidase, alpha-mannosidase, 1.19); mitochondria (malate dehydrogenase, 1.18); endoplasmic reticulum (Tris-resistant alpha-glucosidase, 1.16); basal-lateral membranes (5'-nucleotidase, 1.11) and cytosol (lactate dehydrogenase). Homogenisation in isotonic sucrose containing digitonin (0.12 mmol/litre) selectively disrupted lysosomes and increased the equilibrium density of brush border and basal-lateral membranes. This procedure will be used to study the subcellular pathology of naturally occurring intestinal disease in the dog.
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PMID:Subcellular fractionation studies on peroral jejunal biopsies from the dog. 3 Jan 25

The urinary excretion of adenosine-deaminase-binding protein, a constituent of the brush border of proximal renal tubule cells, has been investigated in 39 patients with disorders associated with malfunction of the renal tubules, and its excretion has been compared with that of two low molecular mass plasma proteins and an enzyme derived from renal tubular cells. None of the 36 patients with disorders associated with chronic renal tubular malfunction were found to be excreting significantly increased quantities of adenosine-deaminase-binding protein but 30 had increased excretion of retinol-binding protein, alpha 1-microglobulin, or N-acetyl-beta-D-glucosaminidase. Measurement of urinary adenosine-deaminase-binding protein may be useful in the assessment of acute renal tubular injuries but it is not of value in the detection of chronic renal tubular disorders.
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PMID:Absence of increased urinary excretion of adenosine-deaminase-binding protein by patients with chronic renal tubular malfunction. 172 56

Tests commonly used to assess the glomerular filtration rate (GFR) and to detect renal tubular damage are critically reviewed. Creatinine clearance which is frequently used for assessment of the GFR is prone to several errors. The plasma creatinine can be used to provide a rough guide but for reliable measurement of the GFR, 51Cr-EDTA clearance is recommended. Measurements of the urinary excretion of low molecular weight proteins, enzymes and kidney tissue proteins have been used to detect tubular damage. Of the low molecular weight proteins excreted, beta-2-microglobulin is unstable and measurement of retinol-binding protein or alpha-1-microglobulin is recommended for the detection of chronic renal tubular malfunction. Of the many enzymes that have been studied, urinary N-acetyl-beta-D-glucosaminidase or alanine aminopeptidase are recommended as being the most useful for the early detection of acute renal tubular damage. Among renal tissue proteins that have been measured in urine adenosine-deaminase-binding protein, a tubular brush border antigen appears to have considerable potential for providing early warning of renal allograft rejection.
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PMID:Assessment of renal function: selected developments. 218 56

A variety of tubular marker proteins, as compared to healthy controls, are excreted at an increased rate in the urine of patients with renal damage. Beside cytoplasmic glutathione-S-transferase and lysosomal beta-N-acetyl-glucosaminidase (beta-NAG) the majority of kidney-related urine proteins derives from membrane surface components of the most vulnerable proximal tubule epithelia, among them ala-(leu-gly)-aminopeptidase, gamma-glutamyl transpeptidase (GGT), the tubular portion of angiotensinase A, the major brush border glycoprotein 'SGP-240' and adenosine-deaminase-binding protein. Urinary tissue proteins, e.g. brush border (BB) microvilli, are immunologically identical with those antigens prepared from cell membranes of the human kidney itself. BB antigens are shed into the urine of patients with glomerulonephritis, interstitial nephritis, systemic diseases, e.g. systemic lupus erythematosus (SLE), diabetes mellitus and multiple myeloma, arterial hypertension, infectious diseases (malaria, AIDS) and after operations, renal grafting and administration of X-ray contrast media, aminoglycosides or certain cytostatics (cis-platinum). Tissue proteinuria of tubular proteins is determined by enzyme-kinetic or quantitative immunological assays applying either poly- or monoclonal antikidney antibodies. Clinical, ultrastructural and histochemical studies support the idea that both 'soluble' and high-molecular-weight membrane particles (vacuolar blebs, greater than 10(6) dalton) as well as microfilamental components of the epithelial cytoskeleton contribute to tubular 'histuria' which appears as a sensitive parameter in monitoring tubular damage under clinical conditions at a very early phase.
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PMID:Urinary proteins of tubular origin: basic immunochemical and clinical aspects. 225 76

Proteins of the isolated brush border membrane of Hymenolepis diminuta were hydrolyzed in vitro by chymotrypsin, papain, pepsin, subtilopeptidase A (= subtilisin Carlsberg), and trypsin. Neither proteolytic nor amidase activity was demonstrable in the isolated membrane using proteinaceous (casein and hemoglobin) or chromogenic (benzoyl-arginine-p-nitroanilide and succinyl-alanyl-alanyl-propyl-phenylalanine p-nitroanilide) substrates, and the membrane preparation did not inhibit the proteolytic and amidase activities of these enzymes. Thus, the isolated tegumental membrane of H. diminuta is not inherently resistant to the action of proteolytic enzymes, and it does not inhibit proteolytic activity. In control incubations containing only buffer, the alkaline phosphatase activity of the brush border membrane decreased in a time dependent manner, but in the presence of chymotrypsin, subtilopeptidase A, and trypsin, the membrane retained greater alkaline phosphatase activity (pepsin and papain could not be tested for this effect on alkaline phosphatase activity). A similar time dependent decrease in activity was also noted for each of the proteolytic enzymes in control assays, but subtilopeptidase A and papain retained greater activity in the presence of the isolated membrane preparation when these assays were compared to controls.
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PMID:Hymenolepis diminuta: interactions of the isolated brush border membrane with proteolytic enzymes. 330 86

Aminooligopeptidase is an intrinsic glycoprotein of the brush border membrane important for hydrolysis of the oligopeptide products of intraluminal protein digestion. To study its synthesis and intracellular processing, we performed pulse-chase experiments using [35S]methionine to label proteins of cultured human intestinal explants obtained by endoscopic biopsy. Aminooligopeptidase was isolated by immune precipitation with a monoclonal antibody and its molecular size was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. A precursor of relative molecular weight (Mr) 127,000 appeared within 10 min of chase and appeared to begin conversion to an Mr 150,000 form (the size of brush border membrane aminooligopeptidase) within 60 min. To determine if the change in molecular size was the consequence of alterations in glycosylation, we studied the susceptibility of the two forms to endo-beta-N-acetylglucosaminidase H, which cleaves immature high-mannose N-linked carbohydrate chains, and to peptide: N4-(N-acetyl-beta-glucosaminyl)asparagine amidase, which cleaves both the high-mannose and complex N-linked carbohydrate chains. Only the early Mr 127,000 aminooligopeptidase was sensitive to endo-beta-N-acetylglucosaminidase H, suggesting that the larger form results from trimming of high-mannose cores and adding terminal sugars in the Golgi complex. Both forms were sensitive to peptide: N4-(N-acetyl-beta-glucosaminyl)asparagine amidase, generating an Mr 114,000 species. The kinetics of the synthesis and processing of aminooligopeptidase and sucrase-isomaltase were compared by immunoprecipitation of both proteins from the same tissue after separating the microvillous membrane from the remainder of the cellular membranes. Labeled aminooligopeptidase was present intracellularly in its mature form within 60 min and was detected exclusively in the brush border membrane by 90 min. Most of the labeled sucrase-isomaltase pool had not yet undergone complex glycosylation during the same period. These data demonstrate that although human intestinal aminooligopeptidase undergoes N-linked glycosylation like sucrase-isomaltase, the synthesis of aminooligopeptidase differs from that of sucrase-isomaltase in respect to the absence of a high-molecular-weight precursor and more rapid pre-Golgi processing.
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PMID:Synthesis and intracellular processing of aminooligopeptidase by human intestine. 336 Feb 63

1. Homogenates of the mucosa of the small intestine of the guinea pig were separated by fractional sedimentation into seven different fractions. The enzymic properties of some of these subcellular fractions were compared with those obtained from the mucosa of the small intestine of the rabbit and cat. 2. The enzymic properties of the low-speed sediment (15000g-min.) were investigated and it was shown that invertase and alkaline ribonuclease were predominantly located in this subcellular fraction, whereas alkaline phosphatase, aryl-amidase, acid phosphatase, acid ribonuclease and phosphoprotein phosphatase, though true constituents of this fraction, occurred to varying degrees in other subcellular structures also. 3. It was shown that the most probable source of the enzymic activities observed in the low-speed sediment was the brush border. Electron micrographs of the purified brush-border fraction indicated vesicles derived from the brush-border membrane. 4. A method is described for the fractionation of mucosal homogenates into a brush border-plus-nuclei fraction, a mitochondrial fraction, a microsomal fraction and a particle-free supernatant. The fractions were shown to be relatively pure, as indicated by the distribution of invertase, DNA, succinate dehydrogenase, glucose 6-phosphatase and 6-phosphogluconate dehydrogenase. 5. Most of the activity of four lysosomal enzymes present in the nuclei-free homogenate was sedimented at 375000g-min., suggesting the occurrence of lysosomal particles in mucosal homogenates. 6. Further fractionation of the microsomal membranes into three fractions is described. The enzymic composition of the membrane fractions is given and discussed in relation to their structure as seen in electron micrographs.
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PMID:Studies on the fractionation of mucosal homogenates from the small intestine. 428 74