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

---

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

S-(4-Bromo-2,3-dioxobutyl)glutathione (S-BDB-G), a reactive analogue of glutathione, has been synthesized and characterized by UV spectroscopy and thin-layer chromatography, as well as by bromide and primary amine analysis. Incubation of S-BDB-G (200 microM) with the 4-4 isoenzyme of rat liver glutathione S-transferase at pH 6.5 and 25 degrees C results in a time-dependent inactivation of the enzyme. The kobs exhibits a nonlinear dependence on S-BDB-G concentration from 50 to 1000 microM, with a kmax of 0.078 min-1 and K1 = 66 microM. The addition of 5 mM S-hexylglutathione, a competitive inhibitor with respect to glutathione, completely protects against inactivation by S-BDB-G. About 1.3 mol of [3H]S-BDB-G/mol of enzyme subunit is incorporated concomitant with 100% inactivation, whereas only 0.48 mol of reagent/mol of subunit is incorporated in the presence of S-hexylglutathione when activity is fully retained. Modified enzyme, prepared by incubating glutathione S-transferase with [3H]S-BDB-G in the absence or in the presence of S-hexylglutathione, was reduced with NaBH4, carboxymethylated, and digested with trypsin. The tryptic digest was fractionated by reverse-phase high-performance liquid chromatography. Two radioactive peptides were identified: Lys82-His-Asn-Leu-X-Gly-Glu-Thr-Glu-Glu-Glu-Arg93, in which X is modified Cys86, and Leu109-Gln-Leu-Ala-Met-CmCys-Y-Ser-Pro-Asp-Phe-Glu-Arg121 , in which Y is modified Tyr115. Only the Lys82-Arg93 peptide was modified in the presence of S-hexylglutathione when the enzyme retained full activity.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:S-(4-Bromo-2,3-dioxobutyl)glutathione: a new affinity label for the 4-4 isoenzyme of rat liver glutathione S-transferase. 195 60

Fibronectins are a class of cell-adhesion proteins produced from a single gene. The soluble plasma form is synthesized by hepatocytes and the insoluble cellular form by fibroblasts and other cell types. The proteins possess multiple binding domains for macromolecules including collagen, fibrin and heparin along with at least one cell-binding domain. Cellular as well as plasma fibronectins are dimers of similar but not identical polypeptides. Their differences are the result of internal amino acid sequence variability due to alternative RNA splicing in at least three regions (ED-A, ED-B and III CS). We have been studying this polymorphism at the protein level in plasma fibronectin (pFn). Cathepsin D-digested pFn applied to a heparin-agarose column and eluted with an NaCl stepwise gradient (0.1 M, 0.25 M and 0.5 M) released two polypeptides (75 kDa and 65 kDa) in the 0.5 M-NaCl peak. Immunoblots with monoclonal antibodies IST-2 (specific for the C-terminal heparin-binding domain) and AHB-3 (specific for the III CS domain) suggest that both peptides contain the C-terminal heparin-binding (Hep-2) domain, but that only the larger fragment possesses the III CS region. These two polypeptides (75 kDa and 65 kDa) were digested with trypsin, and the resulting peptides were analyzed by fast-atom-bombardment mass spectrometry and compared with the known cDNA-derived peptide sequence. Peptides that were unique to the III CS region were further characterized by micro sequence analysis. The 75 kDa fragment is derived from the A-chain and contains the III CS region (89 amino acid residues) along with the C-terminal heparin-binding (Hep-2) domain and the fibrin-binding (Fib-2) domain. A single galactosamine-based carbohydrate group was detected at Thr-73/74 of the III CS region present in the 75 kDa fragment. The 65 kDa fragment is derived from the B-chain and lacks the entire III CS region but does contain the Hep-2 and Fib-2 domains.
...
PMID:Human plasma fibronectin. Demonstration of structural differences between the A- and B-chains in the III CS region. 201 1

Site-directed mutagenesis of smooth muscle myosin light chain kinase was applied to define its autoinhibitory domain. Mutants were all initiated at Leu-447 but contained varying lengths of C-terminal sequence. Those containing the complete C-terminal sequence to Glu-972 possessed kinase activities that were calmodulin-dependent. Removal of the putative inhibitory domain by truncation to Thr-778 resulted in generation of a constitutively active (calmodulin-independent) species. Thus, the inhibitory domain lies to the C-terminal side of Thr-778. Truncation to Lys-793 and to Trp-800 also resulted in constitutively active mutants, although the specific activity of the latter was less than the other mutants. None of the truncated mutants bound calmodulin. For each mutant, the Km values with respect to ATP and to the 20,000-dalton light chain were similar to values obtained with the native enzyme. The presence of the inhibitory domain was detected by activation of kinase activity following limited proteolysis with trypsin. Using this procedure, it was determined that the inhibitory domain was manifest only in the mutant truncated to Trp-800 and was absent from that ending at Lys-793. These results indicate that a critical region of the inhibitory domain is contained within the sequence Tyr-794 to Trp-800. This region overlaps with the calmodulin-binding site for five residues. Our assignment of the inhibitory sequence is consistent with autoinhibition via a pseudosubstrate domain.
...
PMID:Definition of the inhibitory domain of smooth muscle myosin light chain kinase by site-directed mutagenesis. 201 9

The sesquiterpene antibiotic koningic acid (heptelidic acid) has been previously demonstrated to modify glyceraldehyde-3-phosphate dehydrogenase in specific manner, probably by binding to the sulfhydryl residue at the active site of the enzyme (Sakai, K., Hasumi, K. and Endo, A. (1988) Biochim. Biophys. Acta 952, 297-303). Rabbit muscle glyceraldehyde-3-phosphate dehydrogenase labeled with [3H]koningic acid was digested with trypsin. Reverse-phase HPLC revealed that the label is associated exclusively with a tryptic peptide having 17 amino acid residues. Microsequencing and fast atom bombardment mass spectrometry demonstrated that the peptide has the sequence Ile-Var-Ser-Asn-Ala-Ser-Cys-Thr-Thr-Asn-Cys-Leu-Ala-Pro-Leu-Ala-Lys. In comparison to the amino acid sequence of glyceraldehyde-3-phosphate dehydrogenase from other species, this peptide is in a highly conserved region and is part of the active site of the enzyme. The cysteine residue corresponding to the Cys-149 in the pig muscle enzyme, which has been shown to be an essential residue for the enzyme activity, was shown to be the site modified by koningic acid. Structural analyses of the reaction product of koningic acid and L-cysteine suggested that the epoxide of koningic acid reacts with the sulfhydryl group of cysteine residue, resulting in a thioether.
...
PMID:Identification of koningic acid (heptelidic acid)-modified site in rabbit muscle glyceraldehyde-3-phosphate dehydrogenase. 201 92

Recombinant human prorenin (rh-prorenin) was purified from supernatants of Chinese hamster ovary (CHO) cell line transfected with the cDNA for rh-prorenin by employing a simple two-step procedure which consisted of ammonium sulfate precipitation and immunoaffinity chromatography using a monoclonal antibody specific for the profragment of human prorenin. About 100-fold purification with 35% recovery was achieved after the two steps. Purified rh-prorenin migrated as a single protein band with apparent molecular weights of 46,000-47,000 and about 50,000 on SDS-PAGE and gel filtration (HPLC), respectively, although it consisted of multiple components (pI values, 5.6-6.4) that could be resolved by isoelectric focusing (IEF). The treatment of rh-prorenin with endo-beta-N-acetylglucosaminidase converted the rather broad protein band to a sharp band on SDS-PAGE and reduced the number of multiple pI peaks on IEF. Amino-terminal sequence analysis of both the purified rh-prorenin and rh-renin revealed Leu-Pro-Thr-Asp- and Leu-Thr-Leu-Gly-, respectively, which agreed with those predicted from the base sequences of their cDNA. These data suggested that microheterogeneity of rh-prorenin is due to the carbohydrate moiety, but not to the protein moiety. Purified rh-prorenin was almost inactive, but was cleaved at the carboxyl end of a dibasic pair Lys-2-Arg-1 by trypsin and converted to active renin. However, at the early stage during trypsin activation, new intermediate forms between rh-prorenin and rh-renin were formed, suggesting multiple activation steps of rh-prorenin in addition to the one step activation.
...
PMID:Isolation and characterization of recombinant human prorenin in Chinese hamster ovary cells. 201 71

We previously reported a functional defect of von Willebrand factor (vWF) in a new variant of von Willebrand disease (vWD) tentatively named vWD "Normandy." The present work has attempted to characterize the molecular abnormality of this vWF that fails to bind factor VIII (FVIII). The immunopurified vWF from normal and patient's plasma were digested by trypsin and the resulting peptides were compared. The electrophoresis of "vWF Normandy" showed a shift in the band corresponding to a polypeptide from amino acid 1 to 272. Consequently, we performed the molecular analysis of the portion of the vWF gene of this patient encoding this amino acid sequence. Exons 18-24 were amplified by the use of polymerase chain reaction and their nucleotide sequences corresponding to 1.8 kb were determined. Our analysis showed a point mutation C to T at codon 791, resulting in the substitution of Methionine for Threonine at position 28 of the mature vWF subunit. Because this nucleotide substitution destroyed a Mae II restriction site, this mutation was conveniently sought in various individual DNAs. The patterns obtained were consistent with the homozygous and heterozygous state of this mutation in the patient and in her son, respectively, and with its absence in 28 normal individuals. We conclude that Threonine at position 28 in plasma vWF may be crucial for the conformation and FVIII-binding capacity of its cystine-rich N-terminal domain.
...
PMID:The "Normandy" variant of von Willebrand disease: characterization of a point mutation in the von Willebrand factor gene. 201 34

The sequence and blocking group of the amino-terminal 15 amino acids of rabbit trypsin-solubilized cytochrome b5 were determined by liquid secondary ion mass spectrometry (LSIMS) and tandem mass spectrometry (MS/MS). The molecular weights of peptides generated from a Staphylococcus aureus V8 protease digest of this protein were determined by LSIMS analysis and the two peptides containing the blocked amino-terminus were sequenced by tandem mass spectrometry to yield the sequence; N-acetyl-Ala-Ala-Glu-Ser-Asp-Lys-Asp-Val-Lys-Tyr-Tyr-Thr-Leu-Glu-Glu. Comparison of this sequence with a recently reported cDNA sequence (Dariush et al., 1988) indicates that Gln at position 3 is selectively deamidated, although no other discrepancies were found. Intact rabbit and bovine trypsin-solubilized cytochrome b5 were also analyzed by LSIMS on a high-field mass spectrometer equipped with a diode array detector. Mass measurement of the unresolved protonated molecular ion peak tops gave average molecular weights of 9462.2 +/- 2 and 9502.3 +/- 2 for bovine and rabbit trypsin-solubilized cytochrome b5, respectively. In both cases, these molecular weights correspond to a cytochrome b5 fragment consisting of amino acids Asp(7)-Arg(88). The average molecular weight for the rabbit amino-terminal-blocked form of trypsin-solubilized cytochrome b5 was found to be 10,144.5 +/- 2, which was consistent with the molecular weight predicted for the extended N-acetylated form (residues 1-88) of Mr 10,146.1.
...
PMID:Mass spectrometric analysis of rabbit and bovine trypsin-solubilized cytochrome b5. 207 21

Peptide bond formation can be enzymatically catalysed by the reverse reaction of proteases. Application is seen in the industrial production of human insulin. Human insulin derivative can be enzymatically prepared using either porcine insulin or the single chain B(1-29)-A(1-21) insulin precursor as the starting material. This is accomplished by either (1) digesting the starting material at Lys29 with Achromobacter lyticus protease I (Ach) and then coupling with Thr-X (X = blocking residue) (two-step reaction) or (2) subjecting Ala-B30 of porcine insulin or Gly-A1 of the single chain insulin precursor to transpeptidation with Thr-X (one-step reaction). Trypsin and Ach can be used for either type of reaction and, in the immobilized form, for the two-step reaction. Since the single chain insulin precursor can be produced by gene technology (yeast), use of immobilized trypsin or Ach and the two-step reaction using the single chain insulin precursor as the starting material ensures the continuous production of human insulin making it a feasible method for industrial manufacture.
...
PMID:Enzymatic semisynthesis of human insulin: an update. 209 84

Pure 2-amino-3-ketobutyrate CoA ligase from Escherichia coli, which catalyzes the cleavage/condensation reaction between 2-amino-3-ketobutyrate (the presumed product of the L-threonine dehydrogenase-catalyzed reaction) and glycine + acetyl-CoA, is a dimeric enzyme (Mr = 84,000) that requires pyridoxal 5'-phosphate as coenzyme for catalytic activity. Reduction of the hololigase with tritiated NaBH4 yields an inactive, radioactive enzyme adduct; acid hydrolysis of this adduct allowed for the isolation and identification of epsilon-N-pyridoxyllysine. Quantitative determinations established that 2 mol of pyridoxal 5'-phosphate are bound per mol of dimeric enzyme. After the inactive, tritiated enzyme adduct was digested with trypsin, a single radioactive peptide containing 23 amino acids was isolated and found to have the following primary structure: Val-Asp-Ile-Ile-Thr-Gly-Thr-Leu-Gly-Lys*-Ala-Leu-Gly-Gly-Ala-Ser-Gly-Gly -Tyr-Thr-Ala-Ala-Arg (where * = the lysine residue in azomethine linkage with pyridoxal 5'-phosphate). This peptide corresponds to residues 235-257 in the intact protein; 10 residues around the lysine residue have a high level of homology with a segment of the primary structure of 5-aminolevulinate synthase from chicken liver.
...
PMID:2-Amino-3-ketobutyrate CoA ligase of Escherichia coli: stoichiometry of pyridoxal phosphate binding and location of the pyridoxyllysine peptide in the primary structure of the enzyme. 210 56

Previous studies identified synapsin I as a potential substrate for a newly discovered growth factor-sensitive, proline-directed protein kinase originally isolated from rat pheochromocytoma. The present study describes the site-specific phosphorylation of synapsin I by highly purified preparations of proline-directed protein kinase. The incorporation of [32P]phosphate into bovine brain synapsin I was dependent upon both the amount of kinase present and the time of incubation. The maximum stoichiometry of phosphorylation approached 1 mol of phosphate/mol of synapsin I protein. When analyzed by sodium dodecyl sulfate-gel electrophoresis and autoradiography, [32P]phosphate was found to be incorporated into both synapsin Ia and Ib. Phosphoamino acid analysis demonstrated that serine residues were phosphorylated exclusively. Digestion of phosphorylated synapsin I with trypsin followed by high performance liquid chromatography (HPLC) phosphopeptide analysis indicated that the tryptic peptide containing the major phosphorylation site eluted as a single peak at approximately 17% acetonitrile. The primary structure of this phosphopeptide, determined by gas-phase sequencing, was found to be Gln-Ser-Arg-Pro-Val-Ala-Gly-Gly-Pro-Gly-Ala-Pro-Pro-Ala-Thr-Arg-Pro-Pro- Ala-Ser-Pro-Ser-Pro-Gln-Arg. Sequential Edman degradation of this HPLC-purified tryptic phosphopeptide revealed that serine 20 of this peptide was the major phosphorylated residue. This phosphoacceptor site is immediately flanked by a carboxyl-terminal proline residue, an observation that further verifies the proline-directed nature of this protein kinase. The tryptic phosphopeptide corresponds exactly to a sequence in the collagenase-sensitive, proline-rich "tail" region of bovine synapsin I. This novel phosphorylation site is close to but distinct from phosphorylation sites 2 and 3, which are known to be phosphorylated by calcium/calmodulin-dependent protein kinase II and are considered to be of regulatory importance.
...
PMID:Phosphorylation of synapsin I at a novel site by proline-directed protein kinase. 210 63


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

---