Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.1 (chymotrypsin)
10,938 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 hitherto existing results of determinations of enzymatic activities in stool are presented in this review. The chymotrypsin activity is diminished in advanced exocrine pancreatic insufficiency. The faecal alpha-amylase activity has up to now no significance in the diagnosis of pancreatic diseases. Up to five amylolytic enzyme activities are detectable. The alkaline phosphatase is mostly of intestinal origin. Up to 4 enzyme bands can be exhibited with the disc electrophoresis in polyacrylamide gel. Lysozyme and N-Acetyl-beta-D-glycosaminidase can also be detected in stool.
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PMID:[Faecal enzyme diagnostic (author's transl)]. 9 52

The synthetic peptide N-benzoyl-L-tyrosyl-p-aminobenzoic acid is specifically cleaved by chymotrypsin to Bz-Ty and PABA. The liberated PABA is absorbed and excreted in the urine. Accordingly, PABA recovery reflects intraluminal chymotrypsin activity and is an index of exocrine pancreatic function. This test was evaluated in 24 patients with cystic fibrosis to determine its role in the diagnosis of exocrine pancreatic insufficiency. Cumulative percent PABA recovery in six hours was significantly lower in CF patients compared with the control group. No overlap was noted between the two groups. There was good correlation between PABA recovery, fecal chymotrypsin activity, and coefficient of fat absorption. These findings indicate that PABA recovery is significantly reduced in patients with CF and steatorrhea and may prove a practical and reliable test of pancreatic insufficiency.
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PMID:Diagnosis of exocrine pancreatic insufficiency in cystic fibrosis by the synthetic peptide N-benzoyl-L-tyrosyl-p-aminobenzoic acid. 30 53

The oral dose of 2g 4-(N-acetyl-L-tyrosyl) aminobenzoic acid was used to establish the secretion of pancreatic chymotrypsin after stimulation with Lundh's test-meal in 45 persons. By action of chymotrypsin 4-aminobenzoic acid is split in the small intestine. The extent of its excretion in the urine serves as an indicator of exocrine pancreatic secretion. The 4-aminobenzoic acid in the urine is estimated after acid hydrolysis by the diazotation reaction. The average value (x +/- SE) of 4-aminobenzoic acid excreted in an 8-hr urine sample amounts to 69.4 +/- 3.0% with the lower limit of the normal values (x - 2 SD) 49.6%. The corresponding values in patients with pancreatic maldigestion were significantly decreased (25.1 +/- 3.6%). Reduction of the collection period of urine to 6 hrs is sufficient for the demonstration of more advanced forms of pancreatic insufficiency. In cases of disturbances of absorption in the small intestine an extension of the urine collection period to 8 hrs is recommended. We consider this oral test to be a suitable screening method which can be conveniently used in out-patient practice.
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PMID:Functional examination of the pancreatic secretion with 4-(n-acetyl-l-tyrosyl)aminobenzoic acid. 30 23

P-Amino-benzoic acid (PABA) is split specifically by pancreatic chymotrypsin from the synthetic tripeptide N-benzoyl-L-tyrosyl-PABA. The urinary excretion of absorbed PABA serves as an index for exocrine pancreatic function. The peptide (0.015 g/kg) was administered orally to 20 controls (aged between 5 months and 16 years), 6 patients with exocrine pancreatic insufficiency caused by cystic fibrosis (CF), and 9 newborn infants. In the controls the mean 6-hour PABA recovery was 58.5% (+/- 11.2 SD). Recovery in patients with CF was lower (P less than 0.001) with no overlap. In newborn infants the mean 6-hour PABA recovery was 23.4 (+/- 17.7 SD); overlapping in 3 instances with the results in CF patients. This simple, noninvasive test thus appears promising and merits further investigation in younger infants, especially newborns.
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PMID:PABA screening test for exocrine pancreatic function in infants and children. 30 17

A new synthetic substance, N-Benzoyl-L-tyrosyl-p-aminobenzoic acid, is specially cleaved by pancreatic chymotrypsin after oral administration and the released p-aminobenzoic acid (P.A.B.A.) is absorbed and excreted in the urine. The P.A.B.A. recovery in the urine was examined to evaluate its diagnostic value as an exocrine pancreatic function test. The data permit the following conclusions: 1. There is a significant correlation between this test and maximal bicarbonate concentration, amylase output and volume of P.Z./C.C.K. secretin test. 2. More than one-half to two-thirds proximal or one-third distal of the pancreas must be removed before one can expect an abnormal result in this test. 3. This is a simple and useful test to detect exocrine pancreatic insufficiency of more than moderate degree but normal results may be obtained in minimal to mild exocrine pancreatic insufficiency. Only six of 11 cases (54.5%) with one abnormal factor of P-S test showed decreased P.A.B.A. recpvery, whereas 22 of 23 cases (95.7%) with two or three abnormal factors of P-S test showed decreased or borderline P.A.B.A. recovery.
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PMID:Exocrine pancreatic function test by a synthetic peptide. 31 10

An indirect exocrine pancreatic function test (PFT) which measures the ability of a test to hydrolyze a chymotrypsin-labile peptide (N-benzoyl-L-tyrosyl-PABA), was carried out in rats and swine with simulated partial exocrine pancreatic insufficiency. When spray-dried egg white (SDEW), which contains an inhibitor of chymotrypsin, was administered as a test meal with the PFT, the degree of pancreatic insufficiency was more pronounced. The results suggest that SDEW or raw egg while may be useful as a test meal to be given in conjunction with the PFT in humans in order to accentuate moderate degrees of pancreatic insufficiency and improve the sensitivity of this indirect test of pancreatic function.
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PMID:Improved sensitivity of the BTPABA pancreatic function test in animals with meals of raw egg white. 31 25

The synthetic peptide N-benzoyl-L-tyrosyl-p-amino-benzoic acid is selectively metabolized by chymotrypsin. Its derivates are excreted in urine and are taken as a measure of exocrine pancreatic insufficiency. The results of PABA-peptide test, of chymotrypsin activity and of the fat content of faeces were compared with each others in 25 patients suspicious to exocrine pancreatic insufficiency. The results correlate well. Because of the practicability the PABA-peptide test is suggested as an additional routine-method in diagnosis of pancreatic functions although it does not substitute any established method.
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PMID:[The PABA-peptide test: a method in diagnosis of exocrine pancreatic insufficiency (author's transl)]. 31 38

Crude preparations of hog gastric intrinsic factor or their own previously collected gastric juices administered with labeled vitamin B12 did not enhance vitamin B12 absorption in patients with vitamin B12 malabsorption secondary to pancreatic insufficiency. However, when these sources of gastric intrinsic factor were incubated with three times crystallized preparations of insolubilized bovine trypsin or chymotrypsin, the proteolytic enzymes were removed by centrifugation, and the preparations of gastric intrinsic factor were readministered to these patients, the absorption of vitamin B12 was markedly enhanced. Studies of hog gastric intrinsic factor before and after exposure to proteolytic enzymes failed to show any difference on Sephadex chromatography or polyacrylamide gel electrophoresis or on its affinity for vitamin B12 or the ileal receptor in guinea pigs. These investigations demonstrate that: (1) gastric intrinsic factor as secreted by subjects with pancreatic insufficiency or obtained from hog pyloric mucosal extracts is ineffective in promoting vitamin B12 absorption in patients with pancreatic insufficiency, (2) incubation of crude preparations of gastric intrinsic factor with insolubilized pancreatic proteases modified these preparations of gastric intrinsic factor in an as yet undefined manner, allowing them to enhance vitamin B12 absorption, and (3) in vitro studies using gut sacs or brush border preparations do not reflect the abnormality in vitamin B12 absorption associated with pancreatic dysfunction.
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PMID:Evidence that pancreatic proteases enhance vitamin B12 absorption by acting on curde preparations of hog gastric intrinsic factor and human gastric juice. 31 82

Agarose gel electrophoresis (at pH 8.6) was used for qualitative determination of pancreatic enzymes in duodenal juice. The various enzymes were identified by staining techniques with specific chromogenic substrates, by quantitative determination of enzymes in eluates of gel slices, and by immunoelectrophoresis. The various protein bands corresponded to the following enzymes (from the anode to the cathode): chymotrypsin, trypsin, carboxypeptidase A, chymotrypsin, amylase (around the slit), lipase, elastase, and trypsin. The method was applied to a study of exocrine pancreatic function in 10 adults and 83 children suspected of having malabsorption. The duodenal juice, also analyzed for trypsin and amylase content, was collected in fasting condition and after a test meal of water. In patients with normal pancreatic function, all the enzyme bands were present and easy to recognize. In 87 patients carboxypeptidase A was present as two bands in 68 (80%), anodal trypsin as two bands in 39 (45%), and cathodal trypsin as two bands in 85 (97%). Electrophoresis of duodenal juice gave as much information from the fasting sample as after the test meal. Six children with pancreatic insufficiency (cystic fibrosis and Shwachmar's syndrome) had no or only faintly stained enzyme bands and a strongly stained albumin-containing band most anodally. The method is simple, rapid, and useful in routine work. The combination of this qualitative test with a quantitative one (e.g. trypsin determination) provides good information about exocrine pancreatic function.
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PMID:Agarose gel electrophoresis of duodenal juice in normal condition and in children with malabsorption. 43 37


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