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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the esteroproteinases present in the submandibular glands of female mice was purified and characterized. The enzyme, designated proteinase F in this report, had a pI value of 4.6 and a molecular weight of 27600, being comprised of two subunits of 10000 and 18000 daltons. The amino acid composition of proteinase F resembled that of the epidermal growth factor-binding protein, but antiserum against proteinase F only reacted weakly against the binding protein. Proteinase F had an optimum pH at around 9.0 and was strongly inhibited by Cu2+ and Hg2+ (42 and 76% inhibition, respectively, at a concentration of 4 x 10(-6) M). It was also inhibited by aprotinin, phenylmethylsulfonylfluoride, iodoacetamide, leupeptin, antipain, and benzamidine but neither by trypsin inhibitors from pancrease, soybean, or ovomucoid, nor by TLCK, TPCK, and epsilon-amino-n-caproic acid. Although its actual physiological function has yet to be determined, these properties indicate that proteinase F is a new enzyme, being distinguished from known proteinases, kallikrein, plasmin, trypsin, chymotrypsin, tonin, angiotensin-converting enzyme, proteinase A (beta-nerve growth factor endopeptidase), proteinase D (epidermal growth factor-binding protein), P-esterase, renin A, and renin C. Proteinase F was present in the submandibular glands of female mice more abundantly than in those of males, but it increased in males following castration. Thus, proteinase F appears to be affected by male hormones in vivo.
...
PMID:A new esteroproteinase (proteinase F) from the submandibular glands of female mice. 633 33

The vertebrate fatty acid synthetase complex consists of two, apparently identical, subunits which contain seven catalytic centers and an acyl carrier site. As a prelude to studying the functional organization of this system, a comprehensive proteolytic analysis of the chicken fatty acid synthetase subunit has been carried out. Of 24 proteases tested, seven (chymotrypsin, elastase, trypsin, Myxobacter protease, subtilisins A and B, and kallikrein) were found to be capable of inflicting specific cleavages in the native enzyme. The proteolytic profiles were analyzed with respect to both the kinetics and the size of the fragments generated. The relationships between the various fragments were further delineated by combinatorial digestions. All of the data points to the fact that the subunits are indeed identical. The cleavage patterns indicate that the fatty acid synthetase subunit is primarily arranged into three major domains of Mr 127,000, 107,000, and 33,000, since these fragments are commonly produced by most of the proteases. The latter peptides may be further subdivided and mapped by the action of individual enzymes into a number of distinct regions: the 127,000 domain into fragments of Mr 60,000, 45,000, and 23,000; the 107,000 domain into fragments of Mr 14,000, 56,000, 21,000, and 15,000; all aligned accordingly. This proteolytic map serves as a reference for the controlled dissection of the fatty acid synthetase complex, thereby allowing determination of the location of functional centers within the parent polypeptide.
...
PMID:The architecture of the animal fatty acid synthetase. I. Proteolytic dissection and peptide mapping. 636 Oct 30

Prokallikrein was activated by trypsin and by alpha-chymotrypsin, but not by proteases, such as plasmin, thrombin, urokinase, carboxypeptidase B, papain, elastase, pepsin, and cathepsin D. Moreover, rat fresh serum did not activate prokallikrein. Maximum activation of prokallikrein by trypsin was obtained at the concentration of 10 micrograms to 1 mg per ml in PBS and that by alpha-chymotrypsin was at the concentration of 5 mg per ml. The enzymic properties of trypsin-activated and alpha-chymotrypsin-activated kallikreins were identical with those of active kallikrein in the kidney.
...
PMID:Activation of prokallikrein in the rat kidney by proteases. 637 43

The primary structure of human D, the serine protease activating the C3 convertase of the alternative complement pathway, has been deduced by sequencing peptides derived from various chemical (CNBr and o-iodosobenzoic acid) and enzymatic (trypsin, lysine protease, Staphylococcus aureus V8 protease, and chymotrypsin) cleavages. Carboxypeptidase A was also used to confirm the COOH-terminal sequence. The peptides were purified by high-pressure liquid chromatography. The proposed sequence of human D contains 222 amino acids and has a calculated molecular weight of 23 748. It exhibits a high degree of homology with other serine proteases, especially around the NH2-terminus as well as the three residues corresponding to the active-site His-57, Asp-102, and Ser-195 (chymotrypsinogen numbering). This sequence homology is highest (40%) with plasmin, intermediate (35%) with pancreatic serine proteases, such as elastase, trypsin, chymotrypsin, and kallikrein, and least (30%) with the serum enzymes thrombin and factor X. D, however, exhibits only minimal amino acid homology with the other sequenced complement serine proteases, Clr (25%) and Bb (20%). The substitution of a basic lysine for a neutral amino acid three residues NH2-terminal to the active-site serine as well as a small serine residue for a bulky aromatic amino acid at position 215 (chymotrypsinogen numbering) in the binding pocket may be important in determining the exquisite substrate specificity of D. The presence of His-40 which interacts with Asp-194 (chymotrypsinogen numbering) to stabilize other serine protease zymogens [Freer, S. T., Kraut, J., Robertus, J. D., Wright, H. T., & Xuong, N. H. (1970) Biochemistry 9, 1997] argues in favor of such a D precursor molecule.
...
PMID:Amino acid sequence of human D of the alternative complement pathway. 638 66

A protein capable of inhibiting trypsin and other pancreatic proteases has been purified to homogeneity from Escherichia coli by conventional procedures and affinity chromatography. It is stable for at least 30 min at 100 degrees C and pH 1.0, but it is inactivated by digestion with pepsin. The inhibitor has an apparent molecular weight of 38,000 as determined by gel filtration and must be a homodimer since it contains a single 18,000-dalton subunit upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The inhibitor has an isoelectric point of 6.1. One dimeric molecule of the inhibitor can bind two trypsin molecules to form a mixed tetrameric complex, in which trypsin molecules are completely inhibited. The inhibitor is not digested by the trypsin. When N-benzoyl-DL-arginine-p-nitroanilide was used as a trypsin substrate, half-maximal inhibition was observed at 22 nM. This protein also inhibits chymotrypsin, pancreatic elastase, rat mast cell chymase, and human serosal urokinase, but it does not inhibit human pulmonary tryptase, kallikrein, papain, pepsin, Staphylococcus aureus V8 protease, subtilisin, and thermolysin. Surprisingly, it did not inhibit any of the eight soluble endoproteases recently isolated from E. coli (i.e. proteases Do, Re, Mi, Fa, So, La, Ci, and Pi) nor the chymotrypsin-like (protease I) and trypsin-like (protease II) esterases in E. coli. The inhibitor is localized to the periplasmic space and its level did not change with different growth media or stages of cell growth. The physiological function of this E. coli trypsin inhibitor is unknown. We suggest that E. coli trypsin inhibitor be named "Ecotin."
...
PMID:Purification from Escherichia coli of a periplasmic protein that is a potent inhibitor of pancreatic proteases. 641 24

This study was undertaken to confirm our previous preliminary observation that hog pancreas kallikrein (EC 3.4.21.35) directly liberated an angiotensin-like substance from human plasma protein Cohn fraction IV-4 at an acidic pH of 4.0-5.0. First, the possibility of proangiotensin or des-Asp1-angiotensin being the pressor substance was ruled out by t.l.c. Secondly, the pressor substance was purified by Sephadex G-25 and Bio-Gel P-2 gel filtration, and finally by high-performance liquid chromatography. The amino acid composition of the isolated pressor substance (residues/mol) was: Asp, 1.03; Val, 1.03; Ile, 1.00; Tyr, 0.69; Phe, 1.04; His, 0.91; Arg, 0.86; Pro, 0.86. This composition was identical with that of angiotensin. Since the reaction mixture was not contaminated with common proteolytic enzymes, such as trypsin, chymotrypsin, renin, cathepsin D and proangiotensin-converting enzyme, and other enzymes activated by kallikrein, it is clear that hog kallikrein directly produces angiotensin in vitro.
...
PMID:Confirmation of direct angiotensin formation by kallikrein. 655 43

Stimulation of normal rat splenic T cells with pertussigen (lymphocytosis-promoting factor, LPF, from Bordetella pertussis) resulted in the release of a soluble factor that enhanced the glycosylation of IgE-binding factors during their biosynthesis. The soluble factor was detected by the ability of a culture filtrate of LPF-stimulated spleen cells to switch a T cell hybridoma, 23A4, from the formation of unglycosylated IgE-binding factor to the formation of glycosylated IgE-binding factor. The glycosylation-enhancing factor (GEF) had affinity for D-galactose, and the binding of the factor to hybridoma cells via a cell surface galactose was essential for modulation of IgE-binding factors. The GEF was inactivated by irreversible inhibitors of serine proteases such as phenylmethylsulfonyl fluoride, diisopropylfluorophosphate, and p-nitrophenyl ethylpentylphosphonate but was not affected by nonphosphorylating analogues of the organophosphorus compounds. Benzamidine, a competitive and reversible inhibitor of trypsin, also inhibited the glycosylation of IgE-binding factors by GEF. The factor could be purified by absorption to p-aminobenzamidine agarose followed by elution with benzamidine. The capacity of GEF to enhance the glycosylation of IgE-binding factors was inhibited by synthetic substrates of trypsin but not by substrates of chymotrypsin, indicating that GEF is a trypsin-like enzyme. Indeed, trypsin, plasmin, and kallikrein enhanced the glycosylation of IgE-binding factors during their biosynthesis. An inhibitor of trypsin-like enzyme(s), N-alpha-p-tosyl-L-lysine chloromethylketone (TLCK), inhibited trypsin and plasmin but not kallikrein, and TLCK failed to inhibit the GEF-mediated enhancement of glycosylation. It was also found that bradykinin, the biologically active product of cleavage of kininogen by kallikrein, enhanced the glycosylation of IgE-binding factors. The results indicate that GEF is a kallikrein-like enzyme.
...
PMID:Modulation of the biologic activities of IgE-binding factor. IV. Identification of glycosylation-enhancing factor as a kallikrein-like enzyme. 655 15

Human plasma low density lipoproteins (LDL) contain one major apoprotein of apparent Mr = 550,000 designated apolipoprotein B-100 (apo-B-100) and in some LDL preparations, minor components termed apo-B-74 (Mr = 410,000) and apo-B-26 (Mr = 145,000). The structural and metabolic relationships among these LDL apoproteins remain obscure. In the present study, we show that the mixing of proteolytic inhibitors with blood at the moment of collection prevents the appearance of apo-B-74 and -26 in plasma LDL indicating that these peptides are derived by proteolytic degradation of apo-B-100. In order to simulate the degradation in vitro, LDL were digested with plasmin, trypsin, chymotrypsin, thrombin, and tissue and plasma kallikreins and the degradation products analyzed by polyacrylamide gradient gel electrophoresis. While plasmin, trypsin, and chymotrypsin caused extensive degradation of apo-B-100, thrombin, and tissue and plasma kallikreins generated limited cleavage patterns. LDL digested with thrombin contained stoichiometric amounts of two peptides with apparent Mr = 385,000 and 170,000. Mixing experiments showed that the thrombin-derived peptides of apo-B-100 did not co-migrate with apo-B-74 and B-26 during electrophoresis indicating that these peptides were different. In contrast, LDL digested with kallikrein contained stoichiometric amounts of two peptides with apparent molecular weights identical to apo-B-74 and -26. Together, the above results indicate that apo-B-74 and -26 are degradation products of apo-B-100 and are not produced by the action of thrombin. Whether the expression of a kallikrein-like activity in vivo accounts for the specific degradation of LDL B-100 to yield LDL B-74 and -26 remains to be determined.
...
PMID:Degradation of apolipoprotein B-100 of human plasma low density lipoproteins by tissue and plasma kallikreins. 656 30

An enzyme immunoassay for the determination of human urinary kallikrein has been developed and is compared with other human urinary kallikrein assays such as radioimmunoassay, dog blood pressure assay, rat uterus test after kinin liberation and synthetic substrate(20) tests (AcPheArgOEt and S-2266). The usable range of the standard curve is from 0.05 to 12 ng kallikrein per test. The intraassay coefficient of variation is between 2 and 4%, the interassay coefficient of variation is between 4 and 12%, and the recovery of authentic kallikrein added to urine samples is 95%. Human saliva and human pancreatic kallikrein show the same binding curves as purified human urinary kellikrein. Kallikrein from urine of rats, dogs and rabbits as well as boar acrosin and pig pancreatic kallikrein, bovine trypsin and chymotrypsin show no cross-reactivity.
...
PMID:Enzyme immunoassay of human urinary kallikrein. Determination of human urinary kallikrein, III. 675 55

Activation of bovine plasma prekallikrein was investigated with several proteinases. Highly purified bovine plasma prekallikrein was rapidly activated to kallikrein [EC 3.4.21.8] by bovine activated Hageman factor, trypsin [EC 3.4.21.4] and Pronase P (proteinases from Streptomyces griseus) and more gradually by papain [EC 3.4.22.2] and ficin [EC 3.4.22.3]. Activation of prekallikrein was also observed with bovine plasmin [EC 3.4.21.7], but not with bovine clotting factors Xa (Stuart factor) [EC 3.4.21.6] and IXa (Christmas factor) or thrombin [EC 3.4.21.5]. Urokinase [EC 3.4.99.26], Reptilase, collagenase [EC 3.4.24.3], elastase [EC 3.4.21.11], alpha-chymotrypsin [EC 3.4.21.1], Nagarse [EC 3.4.21.14], and stem bromelain [EC 3.4.22 4] did not convert prekallikrein to kallikrein. Plasma kallikrein activated to Hageman factor released kinin rapidly from bovine high molecular weight (HMW) kininogen. However, from bovine low molecular weight (LMW) kininogen, liberation of kinin was extremely slow. The kallikrein activity was inhibited by soybean trypsin inhibitor (SBTI), Trasylol, diisopropylfluorophosphate (DFP), and N-alpha-tosyl-L-lysine chloromethylketone (TLCK), but not by egg-white trypsin inhibitor (EWTI), lima bean trypsin inhibitor (LBTI), heparin or hexadimethrine bromide (Polybrene). The kallikrein formed an enzyme-inhibitor complex with SBTI and Trasylol, but not with LBTI. Prekallikrein did not react with SBTI. Prekallikrein consists of a single polypeptide chain of molecular weight about 90,000, as estimated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Activation of prekallikrein by Hageman factor was found to involve cleavage of the single peptide bond on the disulfide-bridged polypeptide chain, and no change of molecular weight was observed during the activation. The peptide bond cleaved in prekallikrein by the activation was an Arg-X peptide bond on a disulfide-bridged polypeptide chain.
...
PMID:Studies on prekallikrein of bovine plasma. II. Activation of prekallikrein with proteinases and properties of kallikrein activated by bovine Hageman factor. 676 24


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

---