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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A factor (Substance B) has been isolated from brain which reverses the presynaptically-modulated inhibition of evoked ACh release from both guinea-pig myenteric plexus-longitudinal muscle synaptosomes and the intact strip. Inhibitory modulating agents whose activity is reversed by Substance B include oxotremorine, 2-chloroadenosine, clonidine, and morphine. In addition to brain, Substance B is also present in heart and ileum but not in liver or kidney. As determined by Biogel P2 chromatography, this factor appears to have a molecular weight of around 700. It is not destroyed by preincubation with periodate, amylase, adenosine deaminase, pronase, trypsin, phospholipase C or carboxypeptidase Y.
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PMID:Isolation of a factor that reverses presynaptic inhibition of acetylcholine release. 357 23

The exposure of the carboxyl-terminal of the Band 3 protein of human erythrocyte membranes in intact cells and membrane preparations to proteolytic digestion was determined. Carboxypeptidase Y digestion of purified Band 3 in the presence of non-ionic detergent released amino acids from the carboxyl-terminal of Band 3. The release of amino acids was very pH dependent, digestion being most extensive at pH 3, with limited digestion at pH 6 or above. The 55,000 dalton carboxyl-terminal fragment of Band 3, generated by mild trypsin digestion of ghost membranes, had the same carboxyl-terminal sequence as intact Band 3, based on carboxypeptidase Y digestion. Treatment of intact cells with trypsin or carboxypeptidase Y did not release any amino acids from the carboxyl-terminal of Band 3. In contrast, carboxypeptidase Y readily digested the carboxyl-terminal of Band 3 in ghosts that were stripped of extrinsic membrane proteins by alkali or high salt. This was shown by a decrease in the molecular weight of a carboxyl-terminal fragment of Band 3 after carboxypeptidase Y digestion of stripped ghost membranes. No such decrease was observed after carboxypeptidase Y treatment of intact cells. In addition, Band 3 purified from carboxypeptidase Y-treated stripped ghost membranes had a different carboxyl-terminal sequence from intact Band 3. Cleavage of the carboxyl-terminal of Band 3 was also observed when non-stripped ghosts or inside-out vesicles were treated with carboxypeptidase Y. However, the digestion was less extensive. These results suggest that the carboxyl-terminal of Band 3 may be protected from digestion by its association with extrinsic membrane proteins. We conclude, therefore, that the carboxyl-terminal of Band 3 is located on the cytoplasmic side of the red cell membrane. Since the amino-terminal of Band 3 is also located on the cytoplasmic side of the erythrocyte membrane, the Band 3 polypeptide crosses the membrane an even number of times. A model for the folding of Band 3 in the erythrocyte membrane is presented.
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PMID:Carboxypeptidase Y digestion of band 3, the anion transport protein of human erythrocyte membranes. 365 56

The amino acid compositions of the radioactive peptides obtained from trypsin digestion of [14C]benzylpenicillin-labeled penicillin-binding proteins (PBPs) 1A, 1B, and 3 of Escherichia coli have been obtained. Complete digestion of these peptides with a combination of aminopeptidase M and carboxypeptidase Y showed that benzylpenicillin was bound to a serine residue in each of these proteins. Comparison of the compositions of the penicillin-labeled peptides with the complete amino acid sequences of PBPs 1A, 1B, and 3 showed that the acylated serine occurs near the middle of each of the proteins, within the conserved sequence Gly-Ser-Xaa-Xaa-Lys-Pro. The sequence around the acylated serine of these high Mr PBPs shows little similarity to that around the acylated serine of the low-Mr PBPs (D-alanine carboxypeptidases) or of the class A or class C beta-lactamases, except that in all of these enzymes which interact with penicillin the acylated serine residue occurs within the sequence Ser-Xaa-Xaa-Lys.
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PMID:Sequences of the active-site peptides of three of the high-Mr penicillin-binding proteins of Escherichia coli K-12. 392 Jun 58

We studied the amino acid sequence of canine hepatic lysosomal copper protein obtained from Bedlington terriers affected by inherited copper toxicosis. The primary structure was determined by manual Edman degradations and carboxypeptidase Y digestions of peptides generated by cleavage of the S-carboxyamidomethylated and S-aminoethylated protein with trypsin. Although the amino terminus was blocked and heterogeneous, the protein showed extensive sequence homology to mammalian metallothioneins. In particular, all cysteinyl residues were conserved, in agreement with their function as metal ligands. The microheterogeneity observed in the amino-terminal part of the molecule indicated the presence of two isoforms in canine liver like those found in most other mammals studied so far.
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PMID:Canine hepatic lysosomal copper protein: identification as metallothionein. 406 98

We find prompt, high stoichiometry phosphorylation of rhodopsin in response to low fractional rhodopsin bleaching in bovine rod outer segments (ROS). For example, 4 +/- 1 phosphates are incorporated per bleached rhodopsin (Rho*) in 30 sec and 6 +/- 2 phosphates are incorporated in 75 sec in response to bleaching 1% of the rhodopsin in the presence of 1 mM [gamma-32P]ATP and 0.1 mM nonradioactive GTP. Omission of GTP leads to ca 70% inhibition of rhodopsin phosphorylation, presumably due to the GTP-binding protein blocking access of rhodopsin kinase to rhodopsin. Light induced phosphodiesterase (PDE) activation is rapidly quenched in the presence of ATP as first reported by by Liebman and Pugh [Nature 287, 734-736 (1980)]. The kinetics of rhodopsin phosphorylation vary with conditions and from preparation to preparation, however, they are always at least as fast as the ATP dependent quenching of PDE activation. The maximum extent of rhodopsin phosphorylation was limited by specific proteolytic trimming of the carboxyl-terminal phosphorylation sites in washed ROS membranes "stripped" of extrinsic proteins. Membrane preparations with 6,4,2, or 1 phosphate(s) incorporated/Rho* (after a 75 sec post bleach incubation) were produced by treatment with: no protease, carboxypeptidase Y (C), trypsin (T), or both T and C (TC), respectively, followed by reassociation with extrinsic membrane proteins and phosphorylation. Low fractional bleaching was required for maximum phosphorylation/Rho* in membranes which were stripped and reassociated with extrinsic proteins and in isolated ROS. Removal of C-terminal rhodopsin phosphorylation sites has little or no effect on light activation of PDE in the absence of ATP. However, in the presence of ATP the extent of the removal of C-terminal rhodopsin residues has large effects on the light activation and the shut-off of PDE. The single phosphate/Rho* that was added to TC digested membranes reduced the lifetime of Rho* but apparently was not incorporated rapidly enough under our conditions to inhibit the Vmax of PDE. The two phosphates/Rho* which were incorporated after T digestion cause a large decrease in the lifetime of Rho* as well as a decrease in the Vmax of PDE (at low bleaching levels). The four phosphates/Rho* that were added after C digestion further reduce the lifetime of Rho* and the Vmax of PDE. The 6 phosphates/Rho* which were incorporated into the unproteolyzed membranes have little additional effect on Rho* lifetime compared to 4 phosphates/Rho*. However, increasing the phosphorylation observed from 4 to 6 phosphates greatly inhibits the Vmax of PDE at intermediate bleaching levels.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Phosphorylation at sites near rhodopsin's carboxyl-terminus regulates light initiated cGMP hydrolysis. 609 32

A structural comparison between the A and B subunits of the five tetrameric Griffonia simplicifolia I isolectins (A4, A3B, A2B2, AB3, B4) was undertaken to determine the extent of homology between the subunits. The first 25 N-terminal amino acids of both A and B subunits were determined following the enzymatic removal of N-terminal pyroglutamate blocking groups with pyroglutamate aminopeptidase. Although 21 amino acids were common to both subunits, there were four unique amino acids in the N-terminal sequence of A and B. Residues 8, 9, 17, and 19 were asparagine, leucine, lysine, and asparagine in subunit A and threonine, phenylalanine, glutamic acid, and serine in subunit B. The last six C-terminal amino acids, released by digestion with carboxypeptidase Y, were the same for both subunits: Arg-(Phe, Val)-Leu-Thr-Ser-COOH. Subunit B, which contains one methionyl residue, was cleaved by cyanogen bromide into two fragments, a large (Mr = 31,000) and a small (Mr = 2700) polypeptide. Failure of the small fragment to undergo manual Edman degradation indicated an N-terminal blocking group, presumably pyroglutamate. Both subunits were digested with trypsin and the tryptic peptides were analyzed using reverse-phase HPLC. Tryptic glycopeptides were identified by labeling the carbohydrate moiety of the A and B subunit using sodium [3H] borohydride. Cysteine-containing tryptic peptides were similarly identified by using [1-14C]iodoacetamide. Approximately 30% of the tryptic peptides were common to both subunits. Thus, although the N- and C-terminal regions of A and B are similar, the subunits each possess unique sequences.
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PMID:A structural comparison of the A and B subunits of Griffonia simplicifolia I isolectins. 614 93

Pancreatic amylase, elastase 1, elastase 2, cationic trypsin, chymotrypsin, ribonuclease (RNase), phospholipase A2, gamma-glutamyl transpeptidase (gamma-GTP) and pancreatic secretory trypsin inhibitor (PSTI) were purified and characterized from human pancreatic juice and pancreatic tissue. During the purification of these enzymes, two enzymes previously not reported were found. A pancreatic deamidase and a renal endopeptidase were purified and characterized. Specific and reliable radioimmunoassays (RIAs) were developed for all pancreatic enzymes and inhibitor. The purpose of immunoassay for pancreatic enzymes and inhibitor was discussed, and clinical application for the diagnosis of pancreatic diseases was demonstrated. Messenger RNA (mRNA) of amylase was isolated from human pancreas and parotid gland, and used to prepare a complementary DNA (cDNA). The nucleotide sequence and the predicted amino acid sequence of these clones were now being determined. The application of the present investigation to elucidation of pathogenesis of pancreatic enzyme-producing diseases was discussed.
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PMID:[Purification and development of immunoassay of pancreatic enzymes and trypsin inhibitor, and their application to elucidation of pathogenesis of various pancreatic and pancreatic enzyme-producing diseases]. 620 25

Yeast secretory mutants sec53 and sec59 define a posttranslational stage in the penetration of glycoprotein precursors into the endoplasmic reticulum (ER). In the previous report we showed that at the restrictive temperature (37 degrees C) these mutants accumulate enzymatically inactive and incompletely glycosylated forms of the secretory enzyme invertase and the vacuolar enzyme carboxypeptidase Y. Cell fractionation experiments reveal that these precursor forms remain firmly bound to the ER membrane. However, upon return to the permissive temperature (24 degrees C), the invertase precursors are glycosylated, become partially active, and are secreted. Thermoreversible conversion does not require protein synthesis, but does require energy. In contrast to the effect of these mutations, inhibition of oligosaccharide synthesis with tunicamycin at 37 degrees C causes irreversible accumulation of unglycosylated invertase. The effect of the drug is exaggerated by high temperature since unglycosylated invertase synthesized in the presence of tunicamycin at 25 degrees C is secreted. A portion of the invertase polypeptide accumulated at 37 degrees C is preserved when membranes from sec53 and sec59 are treated with trypsin. In the presence of Triton X-100 or saponin, the invertase is degraded completely. The protected fragment appears to represent a portion of the invertase polypeptide that is embedded in or firmly associated with the ER membrane. This association may develop early during the synthesis of invertase, so that in the absence of translocation, some of the completed polypeptide chain remains exposed on the cytoplasmic surface of the ER.
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PMID:Genes required for completion of import of proteins into the endoplasmic reticulum in yeast. 636 72

The assembly activity and electrophoretic mobility of a T4 bacteriophage baseplate protein, P11, have been found to be affected by digestion with the proteases trypsin, subtilisin and carboxypeptidase Y. Analysis of the trypsin limit-digestion product of P11 by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and size analysis by high performance liquid chromatography indicate that there is a decrease of approximately 5000 in the molecular weight of the P11 molecule or a loss of 2500 in Mr from each of the gp11 subunits of the dimer. During protease treatment P11 demonstrates a time-dependent loss in the ability to interact with the baseplate protein P10 to form the P(10/11) complex, the first assembly intermediate of the T4 baseplate 1/6th arm. Similar treatments of the P(10/11) complex indicate that P11 in the complex is not affected by these proteases. Concomitant with the loss of assembly activity is a change in the electrophoretic mobility of P11 on non-denaturing polyacrylamide gels from a single band to a series of more mobile bands suggesting sequential loss of positive charge. P11 assembly activity is completely lost after removal of the first positive charge. These results suggest that the carboxyl termini of the two gp11 subunits of the P11 molecule are involved in the interaction of P11 with P10 to form the P(10/11) complex. Analysis of the portion of gp11 removed by carboxypeptidase Y demonstrates that there are up to 13 aliphatic and aromatic carboxyl-terminal amino acids.
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PMID:Isolation and characterization of precursors in bacteriophage T4 baseplate assembly. III. The carboxyl termini of protein P11 are required for assembly activity. 638 56

The unknown enzymatic mechanism of enhanced protein breakdown in steroid myopathy was studied in functionally and biochemically different muscles of rabbits treated with dexamethasone for three weeks. After glucocorticoid administration the fast-twitch glycolytic semimembraneous muscle of treated animals was atrophied, whereas the weight of the slow-twitch oxidative soleus muscle was not altered. The specific activity of the lysosomal endo- and exopeptidases (cathepsin D, E, B and L, lysosomal carboxypeptidase A and dipeptidylpeptidase I) was increased about 2-fold in the atrophied white muscle. The activity of the cytosol enzyme Ca++-activated neutral proteinase was also elevated, whereas that of the other cytosol endopeptidase, chymotrypsin-like enzyme, was unaltered. The level of alanine aminopeptidase was only slightly increased. On the other hand, there were no unequivocal changes in protease activity in the soleus muscle. These findings are in agreement with the known differences in glucocorticoid-sensitivity of the various muscles. Our results suggest that the lysosomal proteolytic system and the Ca++-activated neutral proteinase may play an important role in the glucocorticoid-induced intracellular protein catabolism in muscle. The inhibitor capacities of cathepsin B and trypsin detectable in muscle cytosol were not altered after steroid treatment. Consequently, the increase in cathepsin B activity was not due to the loss of its inhibitor.
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PMID:Proteases and proteinase inhibitors in experimental glucocorticosteroid myopathy. 676 81


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