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)

Two thiol-activated endopeptidases with pH optima near pH 7.5 were isolated from the supernatant fraction of rabbit brain homogenates by DEAE-cellulose chromatography, gel filtration and isoelectrofocusing. Peptide bond hydrolysis was measured quantitatively by ion-exchange chromatography with an amino acid analyzer. Brain kininase A hydrolyzes the Phe5-Ser6 peptide bond in bradykinin (Bk), Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9. It is isoelectric near pH 5.2 and has a molecular weight of approximately 71 000. The enzyme also hydrolyzes the Phe-Ser peptide bond in Lys-Bk, Met-Lys-Bk, des-Arg1-Bk, Lys9-Bk, Pro-Gly-Phe-Ser-Pro-Phe-Arg, and Gly-Pro-Phe-Ser-Pro-Phe-Arg, but does not hydrolyze (0.1%) this bond in des-Phe8-Arg9-Bk. Brain kininase B hydrolyzes the Pro7-Phe8 peptide bond in Bk. It is isoelectric at pH 4.9 and has a molecular weight of approximately 68 000. Brain kininase B also hydrolyzes the Pro-Phe bond in Lys-Bk, Met-Lys-Bk, Lys9-Bk, Ser-Pro-Phe-Arg, and Phe-Ser-Pro-Arg. Pretreatment of denatured kininogen with brain kininase A or B did not reduce the amount of trypsin-releasable Bk from this precursor protein, indicating that the Bk sequence, when part of a large protein, is not a substrate for either enzyme. However, kininase A and B hydrolyze the octadecapeptide Gly-Leu-Met-Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-Ser-Val-Gin-Val. The data show that a large part of the C-terminal portion of bradykinin is important for the brain kininase A activity and, for both enzymes, the size of the peptide and presumably the residues adjacent to the scissle bond are important in determining the rate of peptide bond hydrolysis by these endopeptidases.
...
PMID:Isolation of brain endopeptidases: influence of size and sequence of substrates structurally related to bradykinin. 0 20

Angiotensin I-converting enzyme (peptidyl dipeptide hydrolase, EC 3.4.15.1) was solubilized from the membrane fraction of human lung using trypsin treatment and purfied using columns of DE 52-cellulose, hydroxyapatite and Sephadex G-200. The purified enzyme was shown to convert angiotensin I to angiotensin II and also to inactivate bradykinin. The specific activity of the enzyme was 9.5 units/mg protein for Hippuryl-His-Leu-OH and 0.665 mumol/min per mg protein for angiotensin I. The enzymic activity obtained after trypsin treatment (1 mg/200 mg protein) for 2 h could be divided into three components: (i) an enzyme of molecular weight 290 000 (peak I), (ii) an enzyme of molecular weight 180 000 (peak II) and (iii) an enzyme of molecular weight 98 000 (peak III), by columns of DE 52-cellulose and Sephadex G-200. Km values of peak I, II and III fraction for Hippuryl-His-Leu-OH were identical at 1.1 mM. pH optimum of the enzyme was 8.3 for Hippuryl-His-Leu-OH.
...
PMID:Purification of angiotensin I-converting enzyme from human lung. 1 71

Brinolase, a fungal protease advocated for thrombolytic therapy, released kinin peptides from semi-purified kininogens of the human, rabbit, guinea pig, and mouse, and moreover cleaved an arginyl bond of the chromogenic peptide S2160. Its kinetics demonstrated marked differences from the mammalian protease trypsin. Whereas trypsin liberated 100% of the available kinin in 30 min at pH 8, brinolase generated a maximum of only 22% under optimal conditions, viz. incubation of 5 microgram/ml enzyme at pH 4.7 for 5 min. Longer incubations yielded less detectable kinin. This maximal release at acidic pH was not due to increased kininogen consumption, nor was it inhibited by the acid protease inhibitor pepstatin. Evidence is presented that brinolase, unlike trypsin, might both release and destroy kinins.
...
PMID:Fungal proteases and the mammalian kinin system: I. Brinolase-catalyzed kinin formation and S2160 hydrolysis. 2 11

Contact activation cofactor (CAC) facilitates the interaction of factors XI and XII. Patients lacking CAC have a coagulation defect and are deficient in high molecular weight kininogen. The coincidence of these two defects suggests that a single protein may be responsible for both physiologic functions. Immunologic and activity studies have been made on isolated CAC to clarify the relationship between CAC and kininogen. CAC forms a single precipitin line with anti-human kininogen, and antikininogen neutralizes CAC activity. CAC and high molecular weight kininogen show a reaction of identity on immunodiffusion against rabbit anti-CAC. Anti-CAC forms two precipitin lines with normal plasma which can be identified as high and low molecular weight kininogen. Monospecific immunoabsorbed anti-CAC forms a single precipitin line with plasma high molecular weight kininogen and neutralizes CAC activity. Cleavage of kinin fragment from CAC by insoluble trypsin or kalikrein does not proportionally reduce procoagulant activity. CAC neutralized by anti-CAC can release kinins on exposure to trypsin or kallikrein. The results support the conclusions that CAC procoagulant activity is a function of high molecular weight kininogen, that antigenic determinants unique to high molecular weight kininogen are shared by the CAC portion of the molecule, and that the clotting reactions may occur at a site removed from the kinin peptide.
...
PMID:Relationship of contact activation cofactor (CAC) procoagulant activity to kininogen. 6 65

Main components of kinin system, the arginine-esterase activity and proteinase inhibitors were estimated in blood serum of patients with nephrotic syndrome of various etiology (glomerulonephritis, amyloidosis, systemic lupus erythematous) and also in patients with latent nephritis and in healthy donors. Content of all the kinin system components (kallikreinogen, kininogen and kininase 1) proved to be increased in all the forms of nephropathy studied. Free kallikrein was found in blood serum of patients with nephrotic syndrome as distinct from healthy persons and patients with latent nephritis. The arginine-esterase activity, which shows the level of trypsin-like proteinases, was altered dissimilarly, depending on the nephrotic syndrome etiology: it was maximally increased in nephrotic syndrome of amyloid genesis and decreased in patient with systemic lupus erythematosus. High content of kallikrein and kininase I with simultaneous decrease in kininogen was typical for patients with severe form of nephrotic syndrome. Impairment of kidney in nephrotic syndrome was also characterized by an increase in alpha1-antitrypsin and in the total antitryptic activity, which reached the maximal value in nephrotic syndrome of the I degree and decreased at the II degree of the disease. In nephrotic syndrome content of alpha2-macroglobulin was maximally increased at the II degree of nephrotic syndrome and decreased in severe form of the disease. The primary alteration in content of proteinase inhibitors and high level of kinin system components were assumed to determine the conditions for activation of kinin system in blood serum and to impair the nephrotic syndrome pathogenesis, which was complicated by systemic manifestations. High content of kinin system components was apparently determined by the increased synthesis in liver tissue in response to inflammation and massive proteinuria; kininase I and alpha2-macrolgobulin, as proteins with high molecular weight, were likely to be selectively retained in blood circulation when the capillary penetration was increased.
...
PMID:[State of the kinin system and level of serum proteinase inhibitors in latent nephritis and the nephrotic syndrome of different etiology]. 7 Jan 11

Three highly specific trypsin-like proteases from mouse submaxillary gland; nerve growth factor gamma subunit, beta nerve growth factor-endopeptidase, and epidermal growth factor-binding protein were tested for kallikrein activity. Low molecular weight kininogen was purified from mouse plasma and used as substrate for the three enzymes, and the kinin released by the enzymes was assayed by its ability to induce contraction of isolated rat uterus. All three enzymes were found to have significant kininogenase activity, and the most active enzyme, beta nerve growth factor-endopeptidase, has activity comparable to authentic kallikreins from other glandular sources. Essentially all of the kininogenase activity of submaxillary gland co-purifies with beta nerve growth factor-endopeptidase. Hence, beta nerve growth factor-endopeptidase appears to be identical with submaxillary gland kallikrein. Nerve growth factor gamma subunit, epidermal growth factor-binding protein, and beta nerve growth factor-endopeptidase have similar amino acid compositions and molecular weights, and are immunologically similar. Comparison of published partial primary sequence data confirms our conclusion that nerve growth factor gamma subunit, epidermal growth factor-binding protein, and kallikrein are very closely related enzymes. It is postulated that these three enzymes are members of a larger family of similar enzymes, all of which are involved in the processing of precursors to polypeptide hormones and growth factors.
...
PMID:The relationship between glandular kallikrein and growth factor-processing proteases of mouse submaxillary gland. 11 Aug 5

Kininogen level, that of active kinins and kininase activity in the plasma of patients suffering from cirrhosis of the liver and of healthy people were studied. The kininogen content was determined by different available methods i.e. the trypsin and acetone techniques and by means of the plasma and glandular kallikrein preparation. An increase in kininase activity and a lowered kininogen level as determined by all the methods were found in the sick persons. The maximal decrease in the kininogen level determined by means of the plasma kallikreins is substantiated in connection with the increased fibrinolytic activity of the plasma of the patients with hepatic cirrhosis.
...
PMID:Studies of the plasma kinin-forming system in cirrhosis of the liver. 16 51

Inibitory effects of [Ethyl p-(6-guanidinohexanoyloxy)benzoate] methanesulfonate (FOY) on kinin formation (in vitro and in vivo) and the fibrinolytic activity (in vivo) were examined and compared with otherinhibitors. Inhibitory effect on kinin forming activity (in vitro) of various enzymes was measured in the guinea pig ileum. FOY and Trasylol inhibited the kinin forming activities of trypsin, pancreas kallikrein and plasma kallikrein. Soybean trypsin inhibitor inhibited kinin like substance was formed in the perfusate when the rat's paw was heated at 46 degrees C. FOY and T-asylol added to the perfusion fluid produced a potent inhibition of the formation of bradykinin-like substance. When administered i.v., FOY and Trasylol did not inhibit the formation of bradykinin-like substance. In the dog, activation of plasmin in the circulatory blood and increase of hemorrhagic tendency were caused by the i.v. administration of human serum plus streptokinase. Such responses were inhibited with a previous i.v. infusion of FOY and t-AMCHA. From the above findings, it may be concluded that FOY has inhibitory effects on kinin formation and fibrinolytic activity.
...
PMID:[Effect of [ethyl p-(6-guanidinohexanoyloxy)benzoate] methanesulfonate (FOY) on kinin formation and fibrinolysis activity]. 16 89

The solubilization of angiotensin I-converting enzyme (peptidyldipeptide hydrolase, EC 3.4.15.1) from rabbit lung was carried out using trypsin treatment. A good recovery of 76% was obtained. The enzyme from solubilized fraction was purified using colums of Sephadex G-200, hydroxyapatite and DEAE-cellulose. The purified enzyme was shown to convert angiotensin I to angiotensin II and also to inactivate bradykinin. The specific activity of the enzyme was 24.3 units/mg protein for hippurylhistidylleucyl hydroxide and 0.182 mumol/min per mg protein for angiotensin I. The enzymic activity obtained after trypsin treatment for 5 h could be divided into two components: (i) an enzyme of molecular weight 300 000 (peak II) and (ii) an enzyme of molecular weight 145 000 (peak III), by Sephadex G-200 gel filtration. The molecular weight of the denatured enzyme was found to be 155 000 by disc gel electrophoresis in the presence of sodium dodecyl sulfate. Km values of peak II and peak III fraction for Hippuryl-His Leu-OH were 2.6 mM.
...
PMID:Solubilization of angiotensin I-coverting enzyme from rabbit lung using trypsin treatment. 18 21

The excretion of kallikrein in urine varies, but the pathophysiologic implications are not clear. To help clarify the role of the urinary kallikrein-kinin system, we have begun to define components of the system as they occur in urine. To minimize artifacts which may arise through extensive purification procedures, we studied urinary protein concentrates prepared by ultrafiltration. The concentrates were separated by chromatography on Sephacryl. Urine contains abundant kininase activity, but in strongly inhibited forms. Kininase II is separable into at least two forms. Another major kininase can hydrolyze benzoyl-Pro-Phe-Arg and is inhibited by arginine but not by BPP9a or SQ 14,225. Its molecular weight is approximately 63,000. A third kininase, not inhibited by BPP9a, is excluded from Sephacryl. Human urine appears to contain only one kallikrein-like enzyme (MW 45,000). In addition, urine contains a protein (MW approximately 80,000) which reacts with trypsin to release bradykinin and which inhibits the hydrolysis of Pro-Phe-Arg-[3H]anilide by urinary kallikrein. Thus, in addition to kallikrein and kinins, urine contains kininogen and at least three kininase enzymes. Urinary ultrafiltrate contains an inhibitory substance (approximately MW 400).
...
PMID:Components of the kallikrein-kinin system in urine. 22 42


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

---