Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of the present study is to elucidate the enzymological and chemical properties of the plasminogen activator in bile, bilokinase. A bilokinase preparation was obtained from 94.2 liters of bovine gall bladder bile through seven purification steps, two of which employed a precipitation method in which ammonium sulfate and acetone were used sequentially. Twenty mg of bilokinase preparation with a specific activity of 5,900 IU/mg were obtained, for a 9% yield with 6,556-fold purification. This preparation revealed a single band upon disc electrophoresis. The bilokinase was a 3.32 S protein and its molecular weight was found to be 57,000. Isoelectric focusing showed that the bilokinase was separable into 5 fractions having different isoelectric points ranging from pH 7.4 to 9.0 The properties of the individual fractions have not yet been determined. The enzymatic activity of bilokinase was recognized to be heat-labile and to be stable at pH 4.0. The activation of plasminogen by bilokinase took place most effectively at pH 7.8 in a manner similar to that of urokinase. In its hydrolysis of both N alpha-acetylglycyl-L-lysine-methyl ester-acetate and H-D-Glu-Gly-Arg-pNA (S-2227), bilokinase showed similar Km values to those of urokinase; however, they were quite distinct from those of plasmin. It was concluded therefore that bilokinase is a plasminogen activator with enzymatic properties which are quite similar to those of the urinary plasminogen activator urokinase. The origin of bilokinase and its relation to liver function are now under investigation.
 ...
PMID:Purification and characterization of the biliary plasminogen activator bilokinase. 621 7

A fluorogenic substrate for plasmin, CBZ-Gly-Pro-Arg-AEC, has been synthesized and used to develop a new sensitive photometric and fluorometric assay of plasminogen activator activity. The fluorescence intensity of free AEC at 460 nm is about 3 orders of magnitude higher than that of acyl-AEC. The release of AEC from the peptidyl derivative was monitored fluorometrically after extraction of free AEC in ethylacetate. Under such conditions, the Km was 0.16 mM. This method was used to monitor the activity of plasminogen activator synthetized by fibroblastic cells (BHK 21 C 13) either released in the supernatants or cell-associated.
 ...
PMID:Sensitive fluorometric determination of plasminogen activator in cell lysates and supernatants. 622 16

Plasminogen activator that is associated with the development of hypersensitivity granulomas (gPA) was partially purified from a saline soluble fraction of murine lepromas elicited in "resistant" mice, C57BL/6N. The gPA was shown to consist of two subspecies (23,000 and 48,000 in molecular weight) with essentially identical enzymologic properties. The gPA was found to be a relatively heat stable weakly alkaline serine proteinase with trypsin-like characteristics in the specificity for synthetic substrates and proteinase inhibitors. It showed a high affinity for H-D-Ile-Pro-Arg-pNA (Km = 1.4 X 10(-4) M) H-D-Val-Leu-Lys-pNA (Km = 5.2 X 10(-4) M), and L-pyroGlu-Gly-Arg-pNA (Km = 9.3 X 10(-4) M). The gPA did not demonstrate antigenic cross reaction with urokinase-type or tissue-type plasminogen activator. Two distinct enzymatic regulators of the gPA were also demonstrated in the saline soluble fraction of the hypersensitivity granulomas. The gPA and its regulation are assumed to be correlated with macrophage activation in the hypersensitivity granulomas.
 ...
PMID:Plasminogen activator and plasminogen activator inhibitor associated with granulomatous inflammation: a study with murine leprosy. 639 70

The behaviour of human urokinase and porcine kidney cell plasminogen activator towards some synthetic substrates has been investigated. Although N- benzyloxycarbonylglycylglycyl -L-arginine 4-methyl-7- coumarylamide (Z-Gly-Gly-Arg-Amc) (I), glutaryl-Gly-Arg-Amc (II) and Z-Gly-Gly-Arg-Val-OMe (III) were substrates, Boc-Gly-Gly-Arg-Val-Val-Gly-Gly-OEt (IV) and Z-Ala-Pro-Gly-Arg-Val-Val-Gly-Gly-OEt (V) were neither substrates nor inhibitors. Steady-state kinetic parameters for the hydrolysis of (II) and (III) by urokinase and porcine kidney cell plasminogen activator were similar.
 ...
PMID:The behaviour of urokinase and porcine kidney cell plasminogen activator towards some synthetic peptides. 653 12

A plasminogen activator, previously designated as rat urinary esterase A (Nustad, K., and Pierce, J. V. (1974) Biochemistry 13, 2312-2319), was separated from kallikrein of rat urine and purified to homogeneity. In polyacrylamide slab gel electrophoresis, the purified enzyme showed three closely migrating protein bands which were labeled with [14C]diisopropylphosphorofluoridate and stained on a zymogram using the chromogenic substrate methionine-alpha-naphthyl ester. Two chains, heavy chain(s) (Mr approximately 15,800, 14,200) and light chain(s) (Mr approximately 8,850, 8,550), were separated in SDS-polyacrylamide gel under reducing conditions, while two bands (Mr approximately 24,500 and 23,000) were seen under nonreducing conditions. The active site of the enzyme was associated with the heavy chain. The purified enzyme was stained for carbohydrate by the periodic acid-Schiff reagent. Five bands were distinguished in slab gel electrofocusing with isoelectric points ranging from 5.05 to 5.45. The purified enzyme lysed fibrin clots containing plasminogen but not plasminogen-free fibrin. It hydrolyzed benzyloxylcarbonyl-Gly-Gly-Arg-amino-4-trifluoromethyl coumarin, and a Km of 53 microM and a Vmax of 63 mumol/min/mg of enzyme were obtained at pH 8.0 and 37 degrees C. The enzyme cleaved kininogen substrates to produce kinin which was measured by bioassay or radioimmunoassay. The enzyme was inhibited by soybean or lima bean trypsin inhibitor, aprotinin, alpha 1-antitrypsin, phenylmethanesulfonyl fluoride, D-Phe-Phe-ArgCH2Cl, antipain, leupeptin, benzamidine, and pentamidine. Its pH optimum was 8.5 to 9.0; it was unstable on dilution and on heating. On immunoelectrophoresis, an antiserum to the esterase formed precipitin arcs with rat plasma and this enzyme at identical positions, which in turn were different from those formed with kallikrein. This urinary enzyme belongs to the family of serine proteinases and is immunologically related to urinary kallikrein.
 ...
PMID:Purification and characterization of rat urinary esterase A, a plasminogen activator. 668 2

Specific inhibiting IgG antibodies were raised in a rabbit using purified human high molecular weight urokinase as antigen. The antibodies reacted with both high molecular weight and low molecular weight human urokinase using an Ouchterlony double-immunodiffusion technique in such a way that one line of complete identity was obtained. Neither precipitation nor functional inhibition was observed for the tissue-type plasminogen activator. Kinetic studies with plasminogen as a natural high molecular weight substrate or the synthetic low molecular weight p-nitroanilide substrate pyro-Glu-Gly-Arg-pNA revealed, for both substrates, mainly a competitive type of inhibition for the Fab fragments of the specific anti-urokinase antibodies. This characterized anti-urokinase IgG was employed to develop a competitive radioimmunoassay, for human urokinase with 125I-labeled urokinase as tracer. In this radioimmunoassay, the lower detection limit for urokinase antigen was 10 pg/ml sample; the intrassay variation was 2.8%, and the interassay variation was 5.3%. Applying this radioimmunoassay to plasma samples obtained from healthy young volunteers, urokinase antigen could be measured in a concentration of 7.82 +/- 3.97 ng/ml for mean and 6.66 +/- 2.39 ng/ml for women (mean +/- SD).
 ...
PMID:Characterization of a specific anti-human urokinase antibody: development of a sensitive competition radioimmunoassay for urokinase antigen. 671 50

The abilities of LHRH and a potent LHRH agonist ([D-Ser-(But),6, des-Gly-NH210]LHRH ethylamide) inhibit FSH responses by rat granulosa cells and Sertoli cells in vitro have been compared. Granulosa cells isolated from 22- or 25-day-old diethylstilbestrol-primed rats and cultured under defined conditions for 48 h with NIH-FSH-S13 (300 ng/ml) or cholera toxin (0.1 microgram/ml) showed increased aromatase activity, as determined by the release of 3H2O from [1 beta-3H]testosterone. LHRH (10(-7) M) or th agonist (10(-8) M) added simultaneously with FSH or cholera toxin inhibited the effects on the release of 3H2O without influencing the protein content of the cell cultures. A smaller stimulation of 3H2O production occurred with (Bu)2cAMP (1.0 mM) plus 3-isobutyl-l-methylxanthine (0.1 mM), and this was partially suppressed in the presence of LHRH or the agonist. Parallel studies with Sertoli cells from 15- or 20-day-old rats demonstrated that culture under appropriate conditions with FSH, cholera toxin, or (Bu)2cAMP (0.5 mM) for 24 h caused an increase in cellular aromatase activity and enhanced secretion into the medium of plasminogen activator. However, no inhibition by LHRH (10(-7) or 10(-9) M) or the agonist (10(-6) or 10(-8) M) occurred when the peptides were added either simultaneously or 24 h before the stimulatory agent. Similarly, Sertoli cells from 11-day-old rats treated daily with LHRH agonist for 5 days in culture, showed no inhibition of aromatase activity after a 4-h stimulation with FSH or (Bu)2cAMP. FSH dose-response curves (0-300 ng/ml) for aromatase activity were shown to be similar after 5 days of culture with or without 10(-8) M LHRH agonist, indicating that the LHRH did not cause a shift in the sensitivity to FSH. The lack of inhibition was seen in Sertoli cell cultures maintained at 37 or 32 C. The enzyme digestion method used to isolated Sertoli cells was not responsible for the lack of effects of LHRH, since cell cultures prepared without the aid of proteolytic enzymes showed similar FSH stimulation of aromatase activity in the presence or absence of 10(-8) M agonist. Further, there was no evidence of degradation of the LHRH agonist when incubated with Sertoli cell cultures. From these studies, we conclude that 1) granulosa cells and Sertoli cells from immature rats differ in their responses to LHRH, and 2) the immature Sertoli cell is an unlikely target for a direct inhibiting influence of LHRH on spermatogenesis.
 ...
PMID:Differential effects of luteinizing hormone-releasing hormone on follicle-stimulating hormone-dependent responses in rat granulosa cells and Sertoli cells in vitro. 678 Mar 24

1. Human uterine cervical stroma was found to contain a Ca(2+)-independent neutral proteinase against casein and N-benzoyl-dl-arginine p-nitroanilide (Bz-dl-Arg-Nan). This enzyme was tightly bound to an insoluble material (20000g pellet) and was solubilized by high concentrations of NaCl or KCl. High concentrations of them in the reaction system, however, inhibited reversibly the activity of this enzyme. 2. The neutral proteinase was partially purified by extraction with NaCl, gel filtration on Sephadex G-200 and affinity chromatography on casein-Sepharose. 3. The optimal pH of this partially purified enzyme was 7.4-8.0 against casein and Bz-dl-Arg-Nan. The molecular weight of the enzyme was found to be about 1.4x10(5) by gel filtration on Sephadex G-200. 4. The enzyme was significantly inhibited by di-isopropyl phosphorofluoridate (0.1mm). High concentration of phenylmethanesulphonyl fluoride (5mm), 7-amino-1-chloro-3-l-tosylamidoheptan-2-one (0.5mm), antipain (10mum) or leupeptin (10mum) was also found to be inhibitory, but chymostatin (40mug/ml), soya-bean trypsin inhibitor (2.5mg/ml), human plasma (10%, v/v), p-chloromercuribenzoate (1mm), EDTA (10mm) and 1-chloro-4-phenyl-3-l-tosylamidobutan-2-one (1mm) had no effect on the enzyme. 5. The neutral proteinase hydrolysed casein, Bz-dl-Arg-Nan and heat-denatured collagen, but was inactive towards native collagen and several synthetic substrates, such as 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-d-Arg, 3-carboxypropionyl-Ala-Ala-Ala p-nitroanilide and 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-d-Arg, and also proteoglycan. The enzyme did not act as a plasminogen activator. 6. These properties suggested that a neutral proteinase in the human uterine cervix was different from enzymes previously reported.
 ...
PMID:Partial purification and characterization of a novel neutral proteinase from human uterine cervix. 699 9

The activation of plasminogen results from proteolytic cleavage of the Arg560-Val561 bond by plasminogen activators (Sottrup-Jensen et al. PNAS (1975) 72, 2577). This region of the zymogen occurs in a small disulfide loop that must restrict the conformation around this bond. The nonapeptide sequence NH2-Cys-Pro-Gly-Arg-Val-Val-Gly-Gly-Cys-NH2 of plasminogen containing the activator sensitive arginyl valine bond was synthesized by carbodiimide coupling of Boc-Cys-Pro-Gly-OH(S-4-methylbenzyl) to NH2-Arg(NO2)-Val-Val-Gly-Gly-Cys-NH2(S-4-methylbenzyl), followed by HF treatment and K3Fe(CN)6 oxidation to form a disulfide bond. Purified peptide was not a substrate for urokinase (UK) or plasminogen activator (PA) but possessed a slightly inhibitory activity towards PA. Addition of a lysine to the N-terminus of the nonapeptide yielded a decapeptide sequence of plasminogen that was a better substrate for UK but not for PA. The decapeptide inhibits PA slightly but not UK. These results suggest that active site geometry for PA must be more restrictive than that of UK and that other regions may be involved in the productive interactions with the activators inducing a better fit of the cyclic peptide loop.
 ...
PMID:Synthesis and properties of cyclic peptides containing the activation site of plasminogen. 717 5

A fibrinolytic agent purified from the haemolymph, hair secretion and whole body extract of Lonomia achelous (Cramer) cleaves various chromogenic peptide substrates. The best substrate were found to be pyro-Glu-Gly-Arg-pNA (S-2444) followed by D-Pro-Phe-Arg-pNA (S-2302) and Bz-Ile-Glu-(or) Gly-Arg-pNA (S-2222) designed for urokinase, plasma kallikrein and factor Xa, respectively. Using substrate S-2251 we also found a plasminogen activator.
 ...
PMID:Studies of a fibrinolytic enzyme from the larvae of Lonomia achelous (Cramer) using chromogenic peptide substrates. 733 Aug 21


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