Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cobalamin (Cbl; vitamin B(12)) malabsorption in pancreatic insufficiency can be partially corrected by bicarbonate and completely corrected by pancreatic proteases but the mechanisms involved are unknown. Because saliva contains enough R-type Cbl-binding protein (R protein) to bind all of the dietary and biliary Cbl, it is possible that R protein acts as an inhibitor of Cbl absorption and that pancreatic proteases are required to alter R protein and prevent such inhibition. To test this hypothesis we studied the ability of R protein and intrinsic factor (IF) to compete for Cbl binding and ability of pancreatic proteases to alter this competition. Human salivary R protein bound Cbl with affinities that were 50- and 3-fold higher than those of human IF at pH 2 and 8, respectively. Cbl bound to IF was transferred to an equal amount of R protein with t((1/2))'s of 2 and 90 min at pH 2 and 8, respectively, and within several hours respective ratios of R protein-Cbl/IF-Cbl of 50 and 2 were observed. Cbl bound to R protein was not transferred to IF at either pH 2 or 8. Incubation of R protein with pancreatic proteases at pH 8 led to a 150-fold decrease in its affinity for Cbl. Incubation of R protein-Cbl with pancreatic proteases led to complete transfer of Cbl to IF within 10 min. Gel filtration studies with R protein-[(57)Co]Cbl and (125)I-R protein showed that pancreatic proteases partially degraded R protein. Pancreatic proteases differed in their ability to effect these changes with trypsin > chymotrypsin > elastase. Pancreatic proteases did not alter IF in any of the parameters mentioned above. Pepsin failed to alter either R protein or IF. THESE STUDIES SUGGEST THE FOLLOWING: (a) that Cbl is bound almost exclusively to R protein in the acid milieu of the stomach, rather than to IF as has been assumed previously; (b) that Cbl remains bound to R protein in the slightly alkaline environment of the intestine until pancreatic proteases partially degrade R protein and enable Cbl to become bound exclusively to IF; and (c) that the primary defect in Cbl absorption in pancreatic insufficiency is a lack of pancreatic proteases and a failure to alter R protein and effect the transfer of Cbl to IF. These studies also suggest that the partial correction of Cbl malabsorption observed with bicarbonate is due to neutralization of gastric HCl, since at slightly alkaline, pH IF can partially compete with R protein for the initial binding and retention of Cbl.
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PMID:Effect of proteolytic enzymes on the binding of cobalamin to R protein and intrinsic factor. In vitro evidence that a failure to partially degrade R protein is responsible for cobalamin malabsorption in pancreatic insufficiency. 2 56

The C-terminal region-sepcific anti-glucagon sera were raised in rabbits using as immunogen, and conjugate of BSA and a C-terminal fragment of pancreatic glucagon. The hapten was prepared by trypsin digestion of the glucagon, which was proved to be a 1:3 mixture of glucagon (18--29) and (19--29). Six rabbits were immunized by subcutaneous injection of an emulsion of the conjugate with complete Freund's adjuvant and five of the rabbits produced antibodies to the glucagon (GC-1, GC-2, GC-3, GC-5 and GC-6). For comparison, rabbit antisera were also produced against glucagon polymer (GA-10) and syrupy glucagon fibrils (PGA-2). All these antisera as well as the pancreatic glucagon-specific antiserum 30 K were characterized with dog gut-extract (gut-GLI) and glucagon-related peptide fragments in the radioimmunoassay systems. The assay systems utilized 125 I-monosubstituted pancreatic glucagon as tracer and human mono-component glucagon as standard. All sera of the GC-series crossreacted with the dog gut-extract very weakly and antisera GC-5 and GC-6 exhibited the lowest crossreactivities with the extract, which were shown to be as low as that of 30k. Characterization of the antiserum GC-5 with purified glucagon related fragments indicated that the major antigenic determinant located exactly in the C-terminal region of glucagon. The present results clearly showed high efficiency of the use of the glucagon C-terminal fragment as hepatenic immunogen in obtaining the C-terminal region-specific, i.e., pancreatic glucagon-specific antisera.
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PMID:Production of anti-glucagon sera with a C-terminal fragment of pancreatic glucagon. 8 40

Pepsin had no effect on the vitamin B12 binder in human saliva (R-binder), while trypsin was found to reduce the apparent molecular weight of the R-binder and to release vitamin B12 from the R-B12complex of human saliva and human gastric juice (HGJ). Trypsin had no effect on the molecular weight and biological activity of intrinsic factor (IF) in HGJ, as demonstrated by gel filtration on Sephadex G-150 and the uptake of IF-B12 by guinea pig intestinal brush borders. An extract of purified guinea pig intestinal lysosomes was also without effect on the molecular weight and the biological activity of IF but was found to release vitamin B12 from the R-B12 complex. The results support the observation that the external pancreatic secretion corrects malabsorption of vitamin B12 by an effect on the non-IF protein in the intestinal juice. Moreover, the results indicate that lysosomal enzymes are not involved in the intestinal absorption of vitamin B12.
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PMID:The effect of proteolytic enzymes on the vitamin B12-binding proteins of human gastric juice and saliva. 12

Prostaglandins biosynthesized from 3H-arachidonic acid by trypsin-dispersed cat adrenocortical cells were isolated by silicic acid and thin layer chromatography. PGE, PGF, and a third component with mobility properties indistinguishable from either PGA or PGB were identified both in cortical cell homogenates and incubation medium. Concentrations of ACTH (125-250 muU) which stimulate steroidogenesis enhanced the conversion of labeled precursor to all three of these prostaglandins. These findings provide further evidence for the proposal that prostaglandins function as a critical link in ACTH-induced steroidogenesis.
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PMID:ACTH-induced prostaglandin biosynthesis from 3H-arachidonic acid by adrenocortical cells. 17 81

1. The reactivities of phenylglyoxal (PGO), glyoxal (GO), and/or methylglyoxal (MGO) with several proteins, including ribonuclease A [EC 3.1.4.22] and its derivatives, alpha-chymotrypsin [EC 3.4.21.1], trypsin [EC 3.4.21.4], lysozyme [EC 3.2.1.17], pepsin [EC 3.4.23.1], rennin [EC 3.4.23.4], thermolysin, and insulin and its B chain, have been examined. From analyses of the reaction products, PGO was shown to be the most specific for arginine residues. GO and MGO also reacted rapidly with arginine residues, but they also reacted with lysine residues to a significant extent. A side reaction with N-terminal alpha-amino groups was observed with each of these reagents. 2. Two arginine residues out of four in ribonuclease A, two out of three in alpha-chymotrypsin, one out of two in trypsin, one out of two in pepsin, and one out of five in rennin appeared to react with PGO fairly rapidly, indicating a difference in the relative accessibility of these residues by the reagent. Extensive modification of the arginine residues by PGO occurred with RCM-derivatives of ribonuclease A and insulin B chain. The N-terminal isoleucine residues of alpha-chymotrypsin and trypsin appeared to be unreactive with PGO because of salt bridge formation with an aspartyl residue. The activity of alpha-chymotrypsin toward N-benzoyl-L-tyrosine ethyl ester and the lytic activity of lysozyme were lost rapidly on treatment with PGO, as in the case of ribonuclease A. Pepsin and rennin were only partially inactivated by reaction with PGO.
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PMID:Further studies on the reactions of phenylglyoxal and related reagents with proteins. 32 41

Pepsin-solubilized collagen I from skin and bone was analyzed with regard to its thermal stability as a triple helical molecule in solution and after in vitro fibril formation. Collagen I from human control bone was compared with samples showing deficiencies or surplus in the degree of hydroxylation of lysine. The helix to coil transitions were studied by circular-dichroism measurements and limited trypsin digestion. Melting of fibrils from standardized in vitro self-assembly was investigated turbidimetrically. Human control bone collagen I has a maximum transition rate (Tm) at 43.3 degrees C in 0.05% acetic acid. This is 1.9 degrees C above control skin (Tm = 41.4 degrees C), most likely, due to a higher degree of prolyl hydroxylation--0.48 in bone vs. 0.41 in skin collagen I. Lysyl overhydroxylation of human and mouse bone collagen I appears to reduce the Tm slightly (approximately 1 degree C). Underhydroxylated bone collagen has a Tm which is 2 degrees C below control. Melting temperatures of in vitro formed fibrils are an indication for higher thermostability in parallel with an increase of lysyl hydroxylation. Accordingly, the melting temperature of such fibrils from human control skin, 49.3 degrees C, exceeds control bone by 1.4 degrees C. The degree of lysyl hydroxylation in these samples is 0.14 and 0.10, respectively. Further underhydroxylation (0.06) reduced it down to 45.4 degrees C, while extensive overhydroxylation did not continue to increase the thermal stability of fibrils.
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PMID:Comparative study on the thermostability of collagen I of skin and bone: influence of posttranslational hydroxylation of prolyl and lysyl residues. 146 61

Extract obtained by ultrasonic disruption of Helicobacter pylori bacteria contained a protein with subunit molecular mass of 25 kD which bound antibodies in sera from patients with H. pylori-associated disease. The protein was purified by gel permeation and elution from SDS-polyacrylamide gel slices, and was used to raise an anti-25-kD protein-specific rabbit serum. Using the antiserum in experiments, the results indicated the following: The protein exists as covalently linked dimers (45 kD) of the 25-kD subunits. Variable numbers of non-covalently linked copies of the dimers make up the native protein. The protein was susceptible to digestion by papain, pronase, and trypsin. Pepsin cleaved off a fragment of approximately 2 kD. A small share of the protein was exposed at the bacterial cell surface, the greatest share being localized internally. The protein was not secreted and it was probably not an integral part of the outer membrane. It was produced in variable quantity by all of 11 H. pylori strains tested and was a major protein in some strains. A cross-reacting protein with subunit size of 25 kD was also produced by Campylobacter jejuni strains, but not by any of a variety of other bacteria. Since both H. pylori and C. jejuni infection occur with a high frequency. the cross-reacting 25-kD protein may interfere unfavourably with the diagnostic specificity of serological tests for infection caused by these bacteria.
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PMID:Characterization of a 25,000-dalton Helicobacter pylori protein, cross-reacting with a Campylobacter jejuni protein. 158 85

Among 51 patients with refractory symptomatic reflux esophagitis seen during an 18-month period, 8 (16%) had undergone previous partial gastrectomy. Either Billroth II (n = 6) or Billroth I (n = 2) resection had been carried out for peptic ulceration 18 months to 30 years beforehand. Each patients was evaluated by symptom scoring, endoscopy, and 24-hour pH monitoring plus a 16-hour esophageal aspiration study, in which 2-hourly aliquots were measured for acid, pepsin, conjugated and unconjugated bile acids, and trypsin. After conversion to a 45 cm Roux-en-Y gastroenterostomy, symptom scoring and endoscopy were repeated at 6 to 12 months in all eight patients. Pepsin, acid, and unconjugated bile acids were seldom present in esophageal aspirates. Conjugated bile acids in concentrations up to 30 mmol/L and trypsin up to 428 micrograms/ml were found in cases of severe esophagitis, mostly during nocturnal rest. Esophagitis, heartburn, regurgitation, and bilious vomiting were eradicated by Roux-en-Y conversion, but other postgastrectomy symptoms (early satiety, dumping, epigastric pain, and diarrhea) were largely unchanged. Postgastrectomy esophagitis resistant to medical therapy seems likely to be caused by nocturnal exposure to trypsin and conjugated bile acids; it is well controlled by a 45 cm Roux-en-Y conversion.
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PMID:Evaluation and surgical correction of esophagitis after partial gastrectomy. 172 72

The present study was carried out to determine the surface hydrophobicity of group A streptococcal strains responsible for rheumatic fever (RF), "rheumatogenic" strains (RG strains) and strains causing glomerulonephritis, "nephritogenic" strains (NG strains) in relation to their adhesion to human pharyngeal cells. Scanning electronmicroscopic (SEM) studies were carried out to the difference, if any, in the adherence of group A streptococci (M type 5) to pharyngeal and buccal cells (PEC and BEC). By employing two techniques for hydrophobicity determination, salt aggregation titre (SAT) and n-hexadecane binding technique, it was observed that RG strains (M5, M1 and M6) were more hydrophobic than NG strain, M49. However, NG strain M12 was almost equally as hydrophobic as RG strains. The adherence of RG strains, except M1 and M24, to PEC was greater in number than that of NG strains. Although M1 strain was hydrophobic, its adherence to PEC was less. Pepsin and trypsin treatment with streptococci reduced the hydrophobicity and adherence of RG and NG strains to PEC. SEM studies revealed firmly adhered indigenous bacteria on PEC and BEC. Streptococci (M5) adhered more to PEC than to BEC. SEM studies also showed that PEC had a peculiar ultrastructural surface feature to which streptococci adhered. These findings suggest that streptococcal hydrophobicity alone does not determine their adhesion to PEC. The surface nature of PEC might be a characteristic feature of the epithelial cells that allows streptococci to adhere and colonize or it might be a consequence of streptococcal adhesion.
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PMID:Surface hydrophobicity of "rheumatogenic" and "nephritogenic" strains of group A streptococci and the ultrastructural surface feature of pharyngeal cells exposed to group A streptococci. 180 57

Fifty two patients with abnormal acid gastro-oesophageal reflux were studied by simultaneous oesophageal pH monitoring and continuous aspiration for 16 hours. Aspirates (from discrete two hour periods) were analysed for volume, pH, bile acids (conjugated and unconjugated), trypsin, and pepsin. The results were compared with pH changes and degree of oesophagitis. Patients with oesophagitis had greater acid reflux than those without, but patients with stricture and Barrett's oesophagus had similar acid reflux to those with uncomplicated erosive oesophagitis. Pepsin concentrations were highest in patients with stricture and Barrett's oesophagus particularly during nocturnal periods. Conjugated bile acids were detected in 75% of patients, mainly during the night, but only 2% of aspirates contained concentrations likely to be cytotoxic. Unconjugated bile acids were not detected, and trypsin was seldom found. Reflux oesophagitis is caused by acid and pepsin. Bile acids and trypsin are probably unimportant.
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PMID:Composition of gastro-oesophageal refluxate. 195 60


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