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:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 427-fold purification of rat urinary kallikrein (RUK) was achieved in three steps involving chromatography on columns of DEAE-Sepharose CL-6B, gel filtration on Sephadex G-100 and affinity chromatography on a column of benzamidine-Sepharose. Purified enzyme showed a single band on SDS-PAGE with an estimated molecular weight of 43,000. The amino-terminal sequences of the first 25 residues of RUK resemble the reported sequence for true kallikrein and share 80% identity with rat submandibular gland (RSMG) kallikrein-like serine protease. The RUK is highly reactive towards kallikrein substrates Bz-pro-phe-arg-pNA and DL-val-leu-arg-pNA, and plasmin substrate D-val-leu-lys-pNA. RSMG enzyme is more reactive towards Bz-val-gly-arg-pNA and tosyl-gly-pro-arg-pNA, preferential chromogenic substrates for trypsin-like proteases and thrombin, respectively. Both leupeptin and aprotinin inhibit RUK strongly, but soy bean trypsin inhibitor has no effect on this enzyme. RSMG enzyme is poorly inhibited by any of these inhibitors. The data suggest that although both enzymes are members of tissue kallikrein multigene family, urinary enzyme is a true kallikrein and RSMG enzyme is a kallikrein-like serine protease with different substrate specificity.
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PMID:Purification of rat urinary kallikrein: comparative studies with rat submandibular gland kallikrein-like serine protease. 128 50

Kallikrein activity in human stomach tissue was measured and found to be about threefold higher in cancer tissue than in normal tissue. To clarify the physiological role of this tissue kallikrein, we investigated its effects on the spontaneous metastasis and tumor growth of Lewis tumors (3LL). Antiprotease, aprotinin, and gabexate mesilate (FOY) inhibited spontaneous metastasis but did not inhibit tumor growth, while tissue kallikrein and plasmin enhanced the spontaneous metastasis of 3LL. The results suggest that the inhibitory effects of aprotinin and FOY on metastasis are not only due to an inhibition of tumor cells released by tissue kallikrein, but that tissue kallikrein, a protease, also participates in metastasis. We thus conclude that aprotinin or FOY should be administered either before or immediately after operation to inhibit spontaneous metastasis.
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PMID:Effect of aprotinin on metastasis of Lewis lung tumor in mice. 138 25

Proteinase species secreted by 10 human gastric carcinoma cell lines were analyzed by gelatin zymography and immunoblotting. These cell lines were classified into the following three groups with respect to proteinase secretion: cell lines secreting mainly gelatinases A and/or B; those secreting multiple types of serine proteinases; and those scarcely secreting these enzymes. Two cell lines of the second group, STKM-1 and MKN28, hardly secreted metalloproteinases but secreted the following four types of serine proteinases: (a) two trypsin-like enzymes (M(r) 26,000 and 24,000 in proenzyme forms); (b) a tissue kallikrein-like enzyme (M(r) 150,000 in a complex form); (c) a plasmin-like enzyme (M(r) 70,000); and (d) a plasminogen activator (urokinase-type, M(r) 57,000, from STKM-1 and tissue-type, M(r) 70,000, from MKN28). The M(r) 70,000 plasmin-like enzyme was also detected at lower levels in the conditioned media of four other cell lines (MKN1, MKN45, NUGC-3, and KATO III). The M(r) 24,000 proenzyme of the trypsin-like enzyme was purified from the serum-free conditioned medium of STKM-1. The proenzyme was activated by enterokinase treatment or autolytically by incubation at neutral pH, decreasing its apparent molecular weight from 24,000 to 23,000 on nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The activated enzyme extensively degraded fibronectin, laminin, and gelatins and to lesser extents type I, III, IV, and V collagens at 30 degrees C. These results suggest that the matrix serine proteinases may play a major role in the matrix degradation by some kinds of human cancer cells.
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PMID:Multiple secretion of matrix serine proteinases by human gastric carcinoma cell lines. 138 87

A plasminogen/plasmin like substance (AHSAA-1), with affinity to lysine column was separated from DEAE-cellulose adsorbed human seminal plasma. Two forms of acidic arginine amidase with different affinities to LBTI (AHSAA-2) and aprotinin columns (AHSAA-3) were separated from the DEAE-cellulose adsorbed preparation and AHSAA-3 was identified as tissue kallikrein. Two basic arginine amidase preparations having affinity to LBTI (BHSAA-1) and aprotinin column were also separated from the CM-cellulose adsorbed human seminal plasma. Three basic arginine amidases with different molecular mass (BHSAA-2 to 4) were separated by Cellulofine GCL-2000 gel filtration from aprotinin adsorbed material and some of their properties were examined.
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PMID:Detection and separation of some arginine amidases including tissue kallikrein from human seminal plasma. 146 64

The substitution of amino acids in the reactive site of aprotinin, a bovine serine proteinase inhibitor with potent activity against trypsin, plasmin and tissue kallikrein, led to a change in specificity of the inhibitor. Twelve new aprotinin variants prepared by recombinant DNA technology and expressed in Escherichia coli clearly demonstrated that the neighbouring groups of the P1 residue, in particular P'2, contribute to the specificity of the inhibitor, while earlier investigations on semisynthetically prepared variants revealed the importance of the P1 residue in dominating the inhibitory specificity. Recombinant aprotinin variants which act specifically against chymotrypsin-like proteinases, were obtained by substitution of the amino acids in position P1 and P'2 by hydrophobic amino acids like phenylalanine, tyrosine and leucine. Some of these variants, particularly those with phenylalanine or leucine substitutions, were also found to exhibit inhibitory activity against cathepsin G with an equilibrium constant of dissociation Ki of 10(-8) M. Inhibitory specificity against cathepsin G was not found in any semisynthetic variant prepared earlier.
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PMID:Recombinant aprotinin homologue with new inhibitory specificity for cathepsin G. 171 53

Human plasma kallikrein, a product of contact-activated plasma proteolysis, is moderately inhibited by aprotinin, a small polypeptide from bovine lung that has been used as an experimental drug in human disease states. Aprotinin has a Lys residue in the P1 (reactive center) position occupying residue 15. Since kallikrein is an arginine-directed serine protease, we hypothesized that an altered form of aprotinin, Arg15-aprotinin, might be a better inhibitor. Kinetic evaluations were performed in 96-well microplates. We found that the KL (loose or Michaelis-Menten complex) was unchanged by the modification. However, the association rate constant was increased from 1.14 X 10(4) (mol/L)-1s-1 to 1.5 X 10(5) (mol/L)-1s1, thus indicating that the inhibition rate was increased 14-fold for the modified protein. The Ki (at equilibrium) was decreased from 3.2 X 10(-7) mol/L to 1.5 X 10(-8) mol/L after substituting Arg for Lys in the P1 position. Therefore, the modified inhibitor binds to plasma kallikrein more tightly than the natural protein. We also investigated the effect of Arg15-aprotinin on tissue kallikrein, plasmin, factor XIIa, factor XIa, and thrombin and found that the Ki slightly decreased from 5.1 X 10(-7) mol/L to 1.2 X 10(-7) mol/L for tissue kallikrein and slightly decreased from 2 X 10(-8) mol/L to 1 X 10(-8) mol/L for plasmin. Arg15-aprotinin did not inhibit thrombin or factor XIIa, even though both enzymes are arginine-directed serine proteases. However, factor XIa, although it was not inhibited by aprotinin, had a Ki of 3.4 X 10(-8) mol/L for Arg15-aprotinin. Therefore, Arg15-aprotinin is a more effective inhibitor of plasma kallikrein as well as factor XIa but shows minimal preference for plasmin and tissue kallikrein. This study also indicates that it is possible and practical to perform kinetic analyses directly in microplates.
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PMID:Kinetics of inhibition of human plasma kallikrein by a site-specific modified inhibitor Arg15-aprotinin: evaluation using a microplate system and comparison with other proteases. 243 87

The nature of vascular permeability factor (VPF) activity derived from serum-free conditioned medium containing cultured human malignant glial tumors has been further investigated. A 1000-fold purification was accomplished by sequential heparin-Sepharose affinity chromatography and high-performance liquid chromatography gel filtration chromatography steps. Vascular permeability factor activity falls into a molecular weight range of 41,000 to 56,000 D. Activity is bound to hydroxylapatite, carboxymethyl-Sepharose, phenyl-Sepharose, and heparin-Sepharose, whereas little or no activity was bound to diethylaminoethyl-Sephacel. Vascular permeability factor activity is trypsin- and pepsin-sensitive but is unaffected by treatment with ribonuclease A. This suggests that VPF is a hydrophobic, positively charged (cationic) polypeptide with a potentially biologically significant affinity for heparin. As most proteins are negatively charged (anionic) and have no affinity for heparin, a significant advantage was gained by performing these purification steps. The activity of VPF is not inhibited by coinjection of conditioned medium with soybean trypsin inhibitor; or hexadimethrine (both known antagonists of tissue plasminogen activator, Hageman factor, and serum kallikrein); or aprotinin (an antagonist of both plasmin and tissue kallikrein); or phenylmethanesulfonyl fluoride (a serine esterase (elastase) inhibitor); or pepstatin-A (an acid protease inhibitor which inactivates vascular permeability-inducing leukokinins). These data, together with the fact that VPF is produced and released into serum-free media, provides substantial evidence against it being one of the more commonly known serum-derived permeability mediators. Treatment with dithiothreitol inhibited VPF activity, indicating the presence of at least one essential disulfide bond in this molecule. Inhibition by dexamethasone of VPF expression in cultured malignant glial cells appears to be selective. Dexamethasone-induced inhibition of VPF was dose-responsive and was not associated with a parallel inhibition of cellular protein synthesis as determined by tritiated leucine incorporation into trichloroacetic acid-precipitable material. Inclusion of dexamethasone in the culture medium was not associated with altered cell viability or cell number. A series of in vivo studies confirmed the inhibition of VPF activity in test animals pretreated with dexamethasone. This steroid-induced inhibition was partially reversed by treatment of test animals with actinomycin D prior to exposure to dexamethasone.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Further characterization of malignant glioma-derived vascular permeability factor. 313 21

A series of acetyl-peptidyl-amides containing the amino acid sequence around the Arg-Ser kallikrein cleavage site of bovine kininogen were synthesized and tested for their ability to inhibit both the kinin-releasing activity and the amidase activity of purified human urinary kallikrein. The substrate analogues were competitive inhibitors for human urinary kallikrein and the heptapeptides (P4-P3'), hexapeptides (P3-P3'), and pentapeptides (P2-P3') gave Ki values of 140, 64, and 18 microM respectively, while the tetrapeptides (P1-P3'), tripeptides (P1'-P3') and dipeptides (P2'-P3') had little or no inhibitory activity. The effective analogues had neither kinin-like nor kinin-blocking activity on the rat uterus either before or after exposure to human urinary kallikrein. The effective human urinary kallikrein inhibitors were further examined for their effect on other serine proteases, including human plasma kallikrein, plasmin, complement components (C1s, C1r), bovine coagulation factors (IIa, IXa, and Xa), elastase, and trypsin. These peptides showed little inhibition of the circulating serine proteases but yielded a Ki for the nonspecific protease trypsin in the microM range. These results should provide the basis for the development of highly specific tissue kallikrein inhibitors to aid in elucidating the in vivo role(s) of tissue kallikreins.
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PMID:Specificity of substrate analogue inhibitors of human urinary kallikrein. 384 67

The synovial tissue kallikrein of rheumatoid patients, arthritic dogs and normal dogs has been partially characterized and estimated. Both human and dog synovial tissue kinin-forming enzyme appears to be distinct from plasmin, plasma kallikrein and pancreatic kallikrein. In three rheumatoid arthritic patients, the mean synovial tissue kallikrein level was found to be 106 +/- 13.5 ng bradykinin equivalents (BK Equiv) per g per min. In nine arthritic dogs the mean synovial tissue kallikrein level, 60.5 +/- 4.5 ng BK Equiv per g per min, was found to be greater (p less than 0.05) than that of five normal dogs (21.6 +/- 5.3 ng BK Equiv per g per min). The possible significance of this finding is discussed.
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PMID:Detection of kallikrein-like activity in inflamed synovial tissue. 655 85

Tissue kallikrein and factor Xa were found to activate tissue plasminogen activator (t-PA) at a rate comparable with that of plasmin. During the activation reaction, the single-chain molecule was converted into a two-chain form. A slight t-PA activating activity was also found in plasma kallikrein. Other activated coagulation factors, factor XIIa, factor XIa, factor IXa, factor VIIa, thrombin and activated protein C had no effect on t-PA activation. t-PA was also activated by a tissue kallikrein-like enzyme that was isolated from the culture medium of melanoma cells. These results indicate that tissue kallikrein and factor Xa may participate in the extrinsic pathway of human fibrinolysis.
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PMID:Proteolytic activation of tissue plasminogen activator by plasma and tissue enzymes. 656 16


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