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)

The interactions of porcine alpha2-macroglobulin (alpha2M) with native proteinases, their zymogens and the chemically-modified enzymes were compared. The alpha2M did not bind to chymotrypsinogen, or to most of the chemically modified derivatives of alpha-chymotrypsin, trypsinogen, DIP- and PMS-trypsins, but it could interact with anhydrotrypsin, PMS-subtilisin, and O-acetylated neutral subtilopeptidase. Anhydrotrypsin appeared to bind very tightly to alpha2M, as does native trypsin, whereas the binding of PMS-subtilisin to alpha2M was weaker than that of the native enzyme, judging from exchange experiments with labeled enzyme and from competitive enzyme assay. There are, however, some differences in the mode of interaction with alpha2M between native and anhydrotrypsins. (1) The shape and the magnitude of ultraviolet difference spectra caused by the interaction with alpha2M were significantly different. (2) The interaction of alpha2M with active proteinase led to the formation of new amino-terminal amino acids, while that with anhydrotrypsin did not. (3) In vivo experiments showed that radioactivity of 3H-labeled trypsin-alpha2M complex was rapidly cleared from the plasma of rats, whereas the anhydrotrypsin-alpah2M complex was cleared very slowly. These results suggest that the proteolytic activity of the enzyme is not obligatory for the first phase of alpha2M-proteinase interaction (formation of Michaelis-type complex), but only the proteolytically modified complex is cleared rapidly from the blood circulation system.
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PMID:Interaction of porcine alpha2-macroglobulin with chemically modified proteinases. 65

The amino acid residues of spinach CF1 subunit delta are identified which are accessible and thus exposed within the quaternary structure of the ATP-synthase complex on the thylakoid membrane. Two types of antibodies in the monospecific polyclonal antiserum 306 against CF1 delta, described in the previous publication [Z. Naturforsch. 44c, 153-160 (1989)], were separated by virtue of their different affinity to thylakoid membranes and used for specific analysis of the products of proteolytic digestion of delta in situ. Polypeptide delta in situ, i.e. within the CF0 CF1 complex on the membrane, is not susceptible to digestion by aminopeptidase M and trypsin, but is shortened by about 1 kDa by carboxypeptidase Y and digested at residues Glu173 and Glu179 by the Staphylococcus aureus protease V8. The epitope on delta reacting with the agglutinating antibodies from serum 306 is lost after these proteolytical treatments and therefore situated on residues Met180-Val187. Since trypsin destroys this epitope only after prolonged incubation and with at least 50 micrograms trypsin/mg Chl, residue Lys169 of delta probably is inaccessible in situ. We conclude that the C-terminal amphipathic alpha-helix of spinach CF1 subunit delta is exposed on the thylakoid membrane, with the hydrophilic face directed to the outside, and that CF1 delta starts to be shielded within the quaternary structure of the CF0 CF1 complex between Glu173 and Lys169. The hydrophobic face of the c-terminal helix may be part of the binding surface towards CF0. Antibodies from serum 306 inhibit the PMS mediated cyclic photophosphorylation by reacting with C-terminal residues of delta.
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PMID:Localization and orientation of subunit delta of spinach chloroplast ATP-synthase within the CF0 CF1 complex. 2. Identification of C-terminal residues of delta, exposed on the thylakoid membrane. 247 16

The ability of Bacteroides gingivalis 381 to attach to hydroxyapatite (HA) beads, treated with either human type I or type IV collagen, or to particles of bovine bone collagen was studied. All preparations were blocked with human albumin prior to being incubated with 3H-thymidine-labeled B. gingivalis 381 cells. The presence of collagen on HA surfaces (C-HA) significantly promoted attachment of the organism. HA treated with Type IV collagen bound B. gingivalis cells more effectively than did HA treated with type I collagen. Attachment of two additional strains of B. gingivalis to HA was also promoted by collagen. Binding to type I or type IV C-HA occurred rapidly, and equilibrium was attained within 45 min. B. gingivalis 381 cells also bound to particles of bovine bone collagen, and this appeared to be biphasic. Heating the bacteria abolished their ability to bind to C-HA. Attachment of B. gingivalis 381 cells to HA treated with type I collagen was strongly inhibited by the presence of soluble type I or type IV collagen, or gelatin, but not by the presence of human albumin, salivary proline-rich protein 1, or saliva. Human serum, fibronectin, fibrinogen, certain protease inhibitors, and some peptides were also inhibitory. 3H-fibronectin bound to bovine bone collagen particles and blocked the attachment of 14C-B. gingivalis cells. Mild trypsin treatment of the fibronectin-collagen complex restored its ability to promote 14C-B. gingivalis attachment concomitant with the loss of 3H-fibronectin. We suggest that elevated levels of proteases in the gingival sulcus, such as are associated with poor oral hygiene and gingivitis, might remove fibronectin and expose collagen molecules in the basement membrane, thereby promoting the attachment of B. gingivalis cells and facilitating their invasion into gingival tissues.
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PMID:Attachment of Bacteroides gingivalis to collagenous substrata. 304 24

By repeated treatments of trypsin with phenylmethylsulfonyl fluoride (PMSF), followed by base elimination of PMS from the PMS-trypsin, a catalytically inactive anhydrotrypsin preparation of low (less than 1%) active trypsin content was obtained. Inactive material was removed by affinity chromatography on trypsin inhibitor-Sepharose 4B and the purified anhydrotrypsin with full binding capacity for trypsin inhibitors was coupled to cyanogen bromide-activated Sepharose 4B. When used below its maximum capacity for trypsin inhibitors the anhydrotrypsin-Sepharose-4B affinity column absorbed both classes of inhibitors present in soybean. When overloaded, the Kunitz type was bound preferentially. Based on this observation, conditions for the partial separation of the two types of inhibitors were worked out.
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PMID:Isolation of soybean trypsin inhibitors by affinity chromatography on anhydrotrypsin-Sepharose 4B. 318 55

An inhibitor of neutral proteinases was isolated from the cytosol of bovine leukocytes by anion exchange chromatography on Mono Q and gel filtration on a HPLC TSK column. The gel filtration resulted in two fractions with inhibitory activity which could be identified by sodium dodecyl sulphate-poly-acrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions as dimer and monomer of the inhibitor. The latter was shown to be homogeneous in SDS-PAGE with an apparent molecular mass of 40 kDa, with calibrated HPLC a molecular mass of 36.5 kDa has been determined. Isoelectric focusing followed by Western blot analysis revealed four bands in the pH range of 5.0 to 5.9. The inhibitor was found in bovine polymorphonuclear neutrophils (PMN), whereas lymphocytes and monocytes lacked this protein. No immunological cross-reactivity between the described cell-derived PMN-inhibitor (PMN-I) and alpha 1-proteinase inhibitor was detectable. The mechanism of inhibition for the serine proteinases chymotrypsin, trypsin, pancreatic elastase and leukocyte elastase was studied. PMN-I could not bind to PMS-chymotrypsin. The reaction of the serine proteinases with the PMN-I was characterized by the determination of the association rate constant kon.
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PMID:Neutral proteinase inhibitors in PMN leukocytes. I. Purification and characterization of a neutral proteinase inhibitor from bovine neutrophils. 342 3

Treatment of chloroplasts with trypsin activates a light-requiring ATPase whose properties are strikingly similar to those of the light-requiring ADP kinase of chloroplasts. The observations here presented suggest that there exists, in chloroplasts, a reducible enzyme which, in its reduced state, catalyzes the reversible reaction: P(i) (-2) + ADP(-3) + H(+) right harpoon over left harpoon ATP(-4) + H(2)O. By reduction and protonation of the catalytic site of this enzyme, light-driven electron flow in the chloroplast drives the reaction to the right. Hydrolysis of ATP proceeds only when the enzyme is reduced and when the proton concentration within the chloroplast is kept at low levels, viz., in the absence of light, in the presence of uncoupling agents which decrease the concentration of internal H(+), or in the presence of electron acceptors which by oxidizing the internal electron acceptors also decrease the proton potential. Activation of the enzyme requires light; it remains active only in the presence of ATP. Hydrolysis of all the ATP results in inactivation of the ATPase. The membrane-bound protein CF(2) limits the reversibility of the reaction by excluding ATP and H(2)O from the enzyme site. It also facilitates the ability of the chloroplasts to accumulate and to maintain high internal concentrations of such ions as ADP, P(i), PMS(+), and imidazole.
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PMID:ADP kinase and ATPase in chloroplasts. 424 Jun 84

A newly discovered small peptide purified from rat follicular fluid stimulates the pituitary to release FSH and LH in vitro as well as in vivo. Dialysates of crude acid extracts of ovarian follicular tissue and fluid from rats pretreated with PMS gonadotropin stimulate the secretion of both LH and FSH, but not PRL, GH, or TSH, in a pituitary monolayer culture system. This stimulating factor, named gonadocrinin for operational facility, is smaller than 3500 daltons; its biological activity disappears after treatment with trypsin. Gonadocrinin is not recognized by two-antisera binding the decapeptide LRF even though D-Phe2,D-Trp6-LR, an LRF analog antagonist, competitively inhibits the activity of ovarian gonadocrinin. Cultured rat granulosa cells also secret substances with gonadocrinin activity in vitro, indicating that the granulosa cells probably are in vivo the source of gonadocrinin. A crude preparation of gonadocrinin given iv to rats on the second day of diestrus induced secretion of LH comparable to that produced by a 250-ng LRF injection. Gonadocrinin has chemical characteristics different from those of LRF. When purified gonadocrinin or LRF was applied to an identical isocratic high pressure liquid chromatography system, LRF was eluted at a position different from that of gonadocrinin, indicating that, chemically, gonadocrinin is not identical to the hypothalamic decapeptide, LRF.
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PMID:Gonadocrinins: peptides in ovarian follicular fluid stimulating the secretion of pituitary gonadotropins. 616 33

The present investigation was designed to study the effect of synthetic ACTH on the synthesis of progesterone, 20 alpha-OH-progesterone and adenosine-3', 5'-monophosphate (cAMP) in isolated luteal cells. Experiments were conducted on rats from three groups. Group I: PMS primed immature rats. Group II: PMS plus hCG primed immature rats. Group III: pregnant rats. Luteal cells were isolated by the Kumai Method (7) using a sucrose density gradient after digestion with trypsin and collagenase. Luteal cells were divided into three fractions; S-1, S-2 and S-3. Following an 18 hr-incubation of S-1 cells of day 7 after PMS injection, a significant increase in progesterone release by ACTH lasted from 6 to 18 hr, whereas 20 alpha-OH-progesterone decreased significantly by ACTH from 8 to 18 hr. There were no differences in progesterone and 20 alpha-OH-progesterone releases from S-2 cells of day 7 between media with and without ACTH. Progesterone release without ACTH reached the peak on day 7 in Group I and on day 6 in Group II. ACTH stimulated progesterone and inhibited 20 alpha-OH-progesterone releases in Groups I and II. The maximum effect of ACTH in both Groups was noted on days 6 and 7. There were no differences in the Effective Dose (ED50) and the Inhibitory Dose (ID50) of ACTH between Group I and Group II. In Group III, releases of progesterone and 20 alpha-OH-progesterone from S-1 cells to media with or without ACTH decreased remarkably after 11 days of gestation. On days, 3, 5 and 8 of gestation, a significant increase in progesterone release from S-1 cells was noted by the ACTH addition. 20 alpha-OH-progesterone release from S-1 cells to media with or without ACTH decreased as the pregnancy advanced. Total cAMP of intra- and extra-cellular S-1 cells (Group II) on day 5 after PMS injection was assayed. ACTH induced an increase in intracellular cAMP. The present results indicate the following: (1) In Group I and Group II, progesterone release increased with the age of the luteal cells and ACTH dose. In Group III, ACTH stimulated progesterone release in a dose-dependent manner in early gestation. (2) 20 alpha-OH-progesterone release decreased by ACTH dose in Group I and Group II, and decreased in Group III as the gestation advanced. (3) Intracellular cAMP increased by ACTH in Group II.
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PMID:[Effect of adrenocorticotropin on progesterone, 20alpha-OH- progesterone and adenosine 3',5'-monophosphate in isolated luteal cells from rat ovaries]. 631 5

1H and 13C NMR titrations were performed on PMS-St. trypsin derived by PMSF modification of Ser 195 in Streptomyces erythraeus trypsin, which is devoid of auto-catalytic degradation activity at pH approximately 8. NMR titration of the imidazole C2 proton showed that His 57 had the pKa value of 6.9 in both native St. trypsin and PMS-St. trypsin, suggesting that the adjacent hydroxyl group of Ser 195 had no effect or a very weak effect on the acid-base properties of the imidazole ring in the catalytic triad. A small change in the chemical shift of the isotopically enriched methylene carbon in the PMS moiety of [methylene-13C]PMS-St. trypsin was observed between pH 6 and 8. The titration curve had an inflexion at pH 6.9 and the mode of transition was apparently sigmoidal, although a Hill coefficient of more than unity was suggested. It is thus likely that His 57 is responsible for this transition. Based on these results, the role of His 57 in the catalytic triad of the active site in serine protease is discussed.
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PMID:NMR titration studies of histidine 57 and the [methylene-13C]PMS group in the phenylmethanesulfonyl (PMS) derivative of Streptomyces erythraeus trypsin. 665 77

An assessment of nine scoring functions commonly applied in docking using a set of 189 protein-ligand complexes is presented. The scoring functions include the CHARMm potential, the scoring function DrugScore, the scoring function used in AutoDock, the three scoring functions implemented in DOCK, as well as three scoring functions implemented in the CScore module in SYBYL (PMF, Gold, ChemScore). We evaluated the abilities of these scoring functions to recognize near-native configurations among a set of decoys and to rank binding affinities. Binding site decoys were generated by molecular dynamics with restraints. To investigate whether the scoring functions can also be applied for binding site detection, decoys on the protein surface were generated. The influence of the assignment of protonation states was probed by either assigning "standard" protonation states to binding site residues or adjusting protonation states according to experimental evidence. The role of solvation models in conjunction with CHARMm was explored in detail. These include a distance-dependent dielectric function, a generalized Born model, and the Poisson equation. We evaluated the effect of using a rigid receptor on the outcome of docking by generating all-pairs decoys ("cross-decoys") for six trypsin and seven HIV-1 protease complexes. The scoring functions perform well to discriminate near-native from misdocked conformations, with CHARMm, DOCK-energy, DrugScore, ChemScore, and AutoDock yielding recognition rates of around 80%. Significant degradation in performance is observed in going from decoy to cross-decoy recognition for CHARMm in the case of HIV-1 protease, whereas DrugScore and ChemScore, as well as CHARMm in the case of trypsin, show only small deterioration. In contrast, the prediction of binding affinities remains problematic for all of the scoring functions. ChemScore gives the highest correlation value with R(2) = 0.51 for the set of 189 complexes and R(2) = 0.43 for the set of 116 complexes that does not contain any of the complexes used to calibrate this scoring function. Neither a more accurate treatment of solvation nor a more sophisticated charge model for zinc improves the quality of the results. Improved modeling of the protonation states, however, leads to a better prediction of binding affinities in the case of the generalized Born and the Poisson continuum models used in conjunction with the CHARMm force field.
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PMID:Assessing scoring functions for protein-ligand interactions. 1516 85


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