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)

A proteinase inhibitor has been isolated from human colorectal adenocarcinomas by extraction with a low-ionic-strength buffer and a combination of Con A-Sepharose, Sephadex G-200, DEAE-cellulose and chromatofocusing steps. The preparation appeared to be homogeneous upon gel exclusion chromatography and SDS-polyacrylamide gel electrophoresis and had an estimated molecular weight of 66,000. The inhibitor was able to bind and inhibit urokinase, plasmin, trypsin, tissue plasminogen activator and thrombin. The binding appeared to be stoichiometric and relatively fast. The isoelectric point of the protein was 4.6-4.7. The inhibitor did not crossreact with antisera elicited against alpha 2-macroglobulin, alpha 2-antiplasmin, antithrombin III or C1-inhibitor, but it did crossreact with an antiserum against alpha 1-antitrypsin in double immunodiffusion. The antiserum only partially attenuated the activity of the inhibitor. Whereas alpha 1-antitrypsin completely inhibited the amidolytic activity of elastase, the tumor inhibitor had no effect on elastase under the same conditions.
...
PMID:Isolation and partial characterization of a proteinase inhibitor from human colorectal adenocarcinoma. 293 82

The turnover of basement membrane macromolecules in injured skeletal muscle has not been studied in contrast to other biologic systems undergoing remodeling. Plasminogen activators and other neutral proteases that are able to degrade these basement membrane macromolecules are secreted by cultured muscle cells. We sought to determine if locally released plasminogen activators could act on basement membrane components. Such degradation might be implicated in the disadhesion of nerve from muscle after motor nerve denervation. To test this hypothesis, we first undertook a study of the sensitivity of muscle extracellular matrix antigens following in vitro exposure to various proteases on frozen muscle sections. Fibronectin was found to be most sensitive, followed by type IV collagen and laminin. Of serine proteases, trypsin was the most active but was not selective, digesting matrix and sarcoplasmic components alike in less than 30 min. Purified urokinase was inactive unless plasminogen (also inactive alone) was previously added to tissue sections, at which time only matrix antigens were digested. Little if any observable degradation of sarcoplasmic proteins took place under these conditions. Using a highly sensitive and selective assay, we found that plasminogen activators were present in muscle tissue and increased 8- to 10-fold after 10 days of denervation. Using an extract of denervated muscle in the presence of plasminogen, we observed degradation of matrix antigens. No degradation was observed with control muscle extract. We next evaluated the degradation of these antigens in denervated muscle during a temporal study. The results, analyzed by quantitative image analysis, indicates that with increasing time after denervation a marked decrease of fibronectin and type IV collagen, followed by laminin occurred but, again, only in the present of plasminogen. These results indicate a selective sensitivity of basement membrane antigens of muscle and a role for plasminogen activators in the degradation of these adhesive basement membranes macromolecules after denervation.
...
PMID:Degradation of muscle basement membrane zone by locally generated plasmin. 294 9

Thirty analogues of leupeptin were synthesized and examined for their inhibitory activities against trypsin, papain, plasmin, kallikrein, thrombin and urokinase in vitro. Benzoyl- and alpha-naphthalenesulfonyl-L-leucyl-L-argininal were 8 times more inhibitory to papain, benzyloxycarbonyl-L-pyroglutamyl-L-leucyl-L-argininal 10 times more to trypsin and plasmin, and DL-2-pipecolyl-L-leucyl-L-argininal 25 times more to kallikrein than leupeptin. Against urokinase, only L-pyroglutamyl-L-leucyl-L-argininal exhibited a potent inhibitory activity. alpha-Naphthalensulfonyl-, dansyl- and benzyloxycarbonyl-(2S,3R)-3-amino-2-hydroxy-4-phenylbutyryl-L-leucyl-L- argininal were inhibitory to thrombin.
...
PMID:Protease-inhibitory activities of leupeptin analogues. 296 94

The plasminogen activator inhibitor 1 (PAI-1) synthesized and released by cultured bovine aortic endothelial cells is present in conditioned medium in a latent form that can be activated by guanidine hydrochloride [Hekman, C. M., & Loskutoff, D. J. (1985) J. Biol. Chem. 260, 11581-11587]. The purified, guanidine-activated PAI-1 was shown to inhibit both plasmin and trypsin in a dose- and time-dependent manner. Second-order rate constants for these interactions were calculated to be 6.6 X 10(5) and 7.0 X 10(6) M-1 s-1 for plasmin and trypsin, respectively. Experiments were conducted to compare the inherently active and the guanidine-activated forms of PAI-1. The two active forms had similar kinetic parameters for interaction with urokinase (Kd, 0.3 pM; kassoc, 1.5 X 10(8) M-1 s-1) and were both inactivated upon treatment with acid or base and by incubation at 37 degrees C. The latent form was relatively stable when incubated under similar conditions. The decrease in PAI-1 activity upon incubation at 37 degrees C was partially restored by a second treatment with guanidine hydrochloride. However, the degree of recovery decreased as a function of incubation time at 37 degrees C. These data suggest that active and guanidine-activated PAI-1 represent a single form of PAI-1. Incubation of this form at 37 degrees C yields two distinct populations of inactive PAI-1, one capable of reactivation and another that appears to be irreversibly inactivated.
...
PMID:Bovine plasminogen activator inhibitor 1: specificity determinations and comparison of the active, latent, and guanidine-activated forms. 296 49

Previous studies of alkali burns have provided evidence for an important role of the plasminogen activator (PA)/plasmin system in corneal ulceration. Current studies have utilized a sensitive, plasminogen-dependent fluorescent assay to demonstrate that PA is present mostly in a latent (trypsin- or plasmin-activatable) form (proactivator) in cultures of rabbit corneal epithelial cells or normal corneas. Cultures of ulcerating corneas demonstrate only active PA early in organ culture, whereas, latent PA levels increase later in culture. Thus, ulceration is correlated with the apparent conversion of latent to active PA. Moreover, profiles of proactivator and latent collagenase and of active PA and active collagenase in vitro, respectively, are similar, suggesting that activator and collagenase are under coordinate control. Cultures of normal epithelial cells and nonulcerating corneas contain PA molecular weight species of 72,000 and 46,000 MW, and ulcer corneas, species of 72,000, 46,000, and 35,000 MW. Double-diffusion analysis indicates that rabbit epithelial cells, fibroblasts, and ulcer corneas produce urokinase (UK)-like PA; and human cornea extracts and tears also contain PA immunoreactive with anti-UK antibodies. The existence of PA in a latent form identifies another level of regulation in the cascades that lead to stromal ulceration.
...
PMID:Latent and active plasminogen activator in corneal ulceration. 298 39

N-terminal analysis of the products of hydrolysis of angiotensin, ACTH and the oxidized B chain of insulin after 4 h incubation with trypsin and urokinase reveals a great qualitative similarity in the action of the two enzymes. As expected, the rates of hydrolysis differ significantly and are much higher in the case of trypsin catalysis than in the case of urokinase catalysis. Unexpectedly, however, a decrease in the difference between the catalytic activity of the two enzymes, by increasing the number of Arg and Lys residues present in the substrate, has been observed.
...
PMID:Action of urokinase and trypsin on angiotensin, ACTH and the oxidized B chain of insulin. 299 38

Human foreskin cells possess sites on their surfaces that specifically bind both active and diisopropylphosphofluoridate-inactivated 2 chain 54 K Da [125I]-urokinase, but do not bind the 54 K Da single chain form of urokinase. 125I-urokinase bound to these sites is not internalized and is very slow to dissociate. There are about 40,000 available binding sites per cell. Brief incubation with pH 2.5 buffer at 5 degrees C unmasks another two to six fold more sites and also extracts plasminogen activator that, based on its accessibility to trypsin, appears to be at the cell surface. This suggests that the cryptic urokinase binding sites could be sites occupied with endogenous plasminogen activator.
...
PMID:Cryptic urokinase binding sites on human foreskin fibroblasts. 300 45

Bis(5-amidino-2-benzimidazolyl)methane (BABIM) is a synthetic aromatic amidine compound which has a number of important biochemical effects, including inhibition of a family of esteroproteases (trypsin, urokinase, plasmin) previously linked to the complex process of tumor invasion. Previous work has suggested that exogenous natural protease inhibitors can block invasion of tumor cells across basement membranes (BM) in vitro. The authors studied the effect of BABIM on the human cell line HT-1080 with the use of a quantitative in vitro amnion invasion assay system. They have verified the ability of these cells to grow in nude mice and metastasize via the lymphatics or blood vessels on the basis of the route of administration of the inoculum. Cells which were able to actively cross the entire BM were trapped on filters and counted by both brightfield microscopy and by beta scintillation counting of cells whose DNA was labeled with tritiated thymidine. In agreement with either counting technique, BABIM, at a concentration of 10(-4) M, significantly inhibited invasion (P less than 0.005) over the 7-day course of the experiments. Under these conditions, the inhibitor was nontoxic and did not alter the attachment of the cells to the amniotic membrane. Furthermore, a highly significant inhibition of invasion (P less than 0.001) was also demonstrated across a variation in molar concentration of BABIM of more than 2 orders of magnitude. Most remarkably, cells were initially inhibited in their ability to invade in the presence of between 10(-9) and 10(-3) M BABIM. Measurement of Type IV specific collagenase in media from these cells shows a significant inhibition of activity in the presence of BABIM. These results suggest two, not necessarily exclusive, alternative interpretations: first, that inhibition of the proteolytic steps along the pathway of activation of basement membrane degrading enzymes results in inhibition of invasion; second, that arginine directed esteroproteases may work in concert with cellular collagenolytic metalloproteinases in the process of invasion by human tumor cells through native matrix barriers.
...
PMID:In vitro inhibition of human sarcoma cells' invasive ability by bis(5-amidino-2-benzimidazolyl)methane--a novel esteroprotease inhibitor. 300 61

Culture medium from rabbit uterine cervical fibroblasts contained a procollagenase and a neutral proproteinase which acts as a procollagenase activator. These two proenzymes have been purified by a combination of ion-exchange, affinity and gel chromatographies. The purified neutral proproteinase showed Mr 60,000 with sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. This neutral proproteinase was activated by trypsin, 4-aminophenylmercuric acetate (APMA) and plasmin, and the active species of the proteinase had Mr 53,000 when activated by APMA; kallikrein and urokinase did not activate this proproteinase. The purified neutral proteinase was inhibited by EDTA, 1,10-phenanthroline and rabbit plasma, but not by serine proteinase inhibitors, suggesting that this proteinase is a metal-dependent proteinase. The purified enzyme could also degrade gelatin, casein, proteoglycan and type IV procollagen. The purified procollagenase had Mr 55,000 and was activated by trypsin, APMA and the active neutral proteinase. These activations were accompanied by decrease in Mr, and the activated species had an Mr which was approx. 10,000 less than that of the procollagenase. In particular, procollagenase activation with neutral proteinase depended on incubation time and proteolytic activity of proteinase. These results indicate that activation of procollagenase by the rabbit uterine neutral proteinase is related to limited proteolysis in the procollagenase molecule.
...
PMID:Procollagenase activator produced by rabbit uterine cervical fibroblasts. 303 65

Certain group A streptococci demonstrate surface receptors that bind selectively to the key fibrinolytic enzyme, plasmin. These bacteria show no reactivity with the zymogen protein plasminogen or with other serine class proteases, such as trypsin or urokinase. Bacterium-bound plasmin retains its ability to cleave synthetic substrates and its ability to hydrolyze a fibrin clot. The bacterium-bound plasmin is not effectively regulated by its physiological regulator, alpha 2-plasmin inhibitor. This study is the first report of a bacterium-associated receptor for plasmin.
...
PMID:Identification of a specific receptor for plasmin on a group A streptococcus. 303 53


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

---