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

Two molecular variants of plasminogen activator (PA): urokinase (uPA) and tissue-type plasminogen activator (tPA), have been reported to be synthesized in the rat testis. Data obtained in this study using monospecific antibodies raised against uPA and tPA in immunoblotting and bioimmunoassay protocols consistently demonstrate that only tPA (and not uPA) is synthesized by bovine Sertoli cell-enriched cultures, and is induced by bovine FSH. Zymographic analysis of conditioned medium on gels containing plasminogen and casein showed a dominant PA proteolytic band (72 kDa) which co-migrated with human tPA. A proteolytic band (43 kDa), which was also secreted by FSH-stimulated cells, was not present when protection was afforded from auto-proteolysis by aprotinin, and was therefore concluded to be a proteolytic fragment of tPA, and not uPA.
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PMID:Only tissue-type plasminogen activator is secreted by immature bovine Sertoli cell-enriched cultures. 312 22

Elevated levels of plasminogen activator (PA) activity have been correlated with neoplasia and may have an important role in tumor-cell invasion and metastasis. We have developed a new caseinolytic assay that uses an immunochemical approach to measure the activity of PA elaborated by malignant tumor cells. The highly sensitive assay consists in incubating a source of PA (viable tumor cells, cell extracts, or conditioned medium) with purified plasminogen in microtiter plates precoated with a suitable protein substrate such as casein. Clearance of the immobilized protein substrate by PA-generated plasmin is then measured by a technique based on the enzyme-linked immunosorbent assay. In experiments using urokinase as a source of PA, the assay displayed near linearity over several log units of urokinase activity and could detect as little as 10(-2) Ploug units of PA activity. Besides successfully measuring PA activity produced by the human HT 1080 fibrosarcoma cell line, the assay permitted detection of significant plasminogen-independent proteolytic activity generated by intact tumor cells cultured in direct contact with immobilized protein substrates.
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PMID:Measurement of plasminogen activator activity from human fibrosarcoma cells by a new microassay. 369 27

In a series of 46 cases of primary mammary ductal carcinoma, immunohistochemical markers of differentiation (casein, human placental lactogen, alphalactalbumin, pregnancy specific beta-1 glycoprotein, secretory component, CEA, and peanut lectin agglutinins [PLA]), were quantitated via point-counting. An immunoperoxidase bridge (PAP) was used to identify all except the PLA, in which an avidin-biotin complex with alkaline phosphatase development was employed. For none of the markers was there any difference in the quantity present in tumors of patients who had recurred versus the tumors of patients who had enjoyed a minimum of five years disease-free survival. Nonneoplastic epithelium was only rarely positive for these markers. Although eventually surmounted, technical problems significantly hampered application of morphometry to this histochemical material. The authors conclude that these markers have little relationship to differentiation toward mammary duct epithelium and that they do not provide significant prognostic information in patients with breast cancer.
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PMID:Correlation of immunohistochemical markers with patient prognosis in breast carcinoma: a quantitative study. 609 96

Enzymatic activity was investigated in metal-binding proteins from rat epidermal cells. Tris-HCl buffer soluble and KSCN solubilized proteins were extracted stepwise from granular and cornified cells of 2-day old rat epidermis. Each extract was separately applied to a Cu2+ or Zn2+ chelate Sepharose 6B column and the proteins were eluted with buffers of different pHs and finally with EDTA solution. Metal chelate-binding proteins were found in both soluble and solubilized proteins but there was a larger amount in the latter. Affinity of the proteins to bind with Cu2+ chelate was greater than that with Zn2+ chelate. In Tris-HCl buffer extract, histidase activity was detected in Cu2+ chelate-binding proteins, but not in Zn2+ chelate-binding proteins. Acid phosphatase, cysteine proteinase, dipeptidase, cathepsin D, beta-galactosidase, gelatin hydrolase, and superoxide dismutase did not bind to metal chelates although these enzymes, except acid phosphatase, were inhibited by Cu2+, but not by Zn2+. In contrast, KSCN solubilized metal chelate-binding proteins showed plasminogen activator, acid phosphatase, and gelatin and casein hydrolases while histone hydrolase did not bind to either chelate column. Since metal-binding proteins in rat epidermal cells have been shown previously to be histidine- and cysteine-rich proteins concentrated in keratohyalin granules, interaction of metals and the structural proteins with certain enzymes may be involved in the regulation of epidermal cell functions.
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PMID:Enzymatic activity of metal-binding proteins in epidermal cells. 653 44

In the MCF7 human breast cancer cell line, estradiol stimulates the synthesis of a 52 K secretory glycoprotein and has been reported to increase the plasminogen activator (PA) activity in the culture medium. Since one PA isozyme has a molecular weight close to 52 000 daltons under denaturing conditions, we asked whether the 52 K protein was a PA. The PA activity released in serum-free conditioned medium was evaluated by the increase in [125I]casein digestion observed in the presence of plasminogen. The 52 K protein was estimated by analysing the released proteins on SDS-polyacrylamide gel electrophoresis. When the conditioned medium was chromatographed on concanavalin A-Sepharose, the 52 K protein was retained on the gel, but not the PA. The two proteins also appeared different on the basis of their competing efficiency in a radioimmunoassay developed to quantify the 52 K protein. An antiserum against human urokinase failed to immunoprecipitate the 52 K protein. Under our culture conditions estradiol increased 52 K, but not PA, production. These results clearly indicate that the estradiol-regulated 52 K protein is not a plasminogen activator.
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PMID:The estrogen-regulated 52 K protein adn plasminogen activators released by MCF7 cells are different. 653 16

Urokinase, a plasminogen activator found in urine is used in the treatment of pulmonary embolism, and is supplied commercially by several companies in Europe, U.S.A. and Japan. It exists in two forms, of molecular weights 50-55 000 and 33 000 daltons, which may differ in their therapeutic efficiency. A variety of assay systems exist to measure plasminogen activator activity--clot lysis, casein hydrolysis, amidolytic cleavage of synthetic peptide substrates. These assays are time-consuming, relatively insensitive, and cannot accurately assess the amount of the two molecular species in any preparation of urokinase. Standardization therefore presents a problem to manufacturers, control agencies, and clinicians. We have prepared a variety of monoclonal antibodies to human urokinase and have assessed their value as standardizing different commercial preparations of urokinase and measurement of urokinase for therapeutic monitoring.
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PMID:Possible use of monoclonal antibodies to standardize the production and use of human urokinase. 654 1

The molecular sizes of secreted and cell-associated plasminogen activators from four cultured cell types were determined using an SDS-PAGE technique in which plasminogen and casein were included during polymerization of the polyacrylamide gel. The major bands of plasminogen activators secreted by human neonatal epidermal cells, human adult epidermal cells and transformed human squamous cells migrated the same distance as the high molecular weight band of authentic urokinase, indicating that the apparent molecular weight of these plasminogen activators was approximately 55,000 daltons. Plasminogen activator extracted from normal adult human epidermis also migrated with this major band of plasminogen activator, and a minor higher molecular weight band was also detected. In contrast, plasminogen activators secreted by transformed mouse squamous cells migrated between the high molecular weight band (approximately 55K) and the low molecular weight band of urokinase (approximately 32K), indicating that plasminogen activators of mouse epidermal cells differ from those of human epidermal cells. The mobility of the major bands of plasminogen activators detected in cell lysates of the four cell types was identical to that of secreted plasminogen activators.
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PMID:Molecular size of secreted and cell-associated plasminogen activators from cultured epidermal cells. 668

Plasma membranes isolated from normal thymocytes of hamster and rats were found to exhibit neutral protease activity toward 125I-labeled casein. The plasma membrane-associated proteases were completely inhibited by the serine protease inhibitors, diisopropyl fluorophosphate, phenylmethylsulfonyl fluoride and p-nitrophenyl-p-guanidinobenzoate, partially inhibited by soybean trypsin inhibitor and antipain, but were only weakly inhibited by L-1-tosylamino-2-phenylethyl chloromethyl ketone. The plasma membrane-associated proteases were also completely inhibited by ZnCl2 (75--100 mu M), but they were not affected by several other divalent cations. The plasma membrane fraction contained a plasminogen activator activity which was specifically localized in this fraction. The plasma membrane-associated plasminogen activator activity was inhibited by all of the inhibitors which inhibited plasma membrane-associated proteases except L-1-tosylamido-2-phenylethyl chloromethyl ketone. Labeling of plasma membrane-associated serine esterases with [3H] diisopropyl fluorophosphate followed by separation of the proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that this fraction contained a single major 3H-labeled protein of Mr 105 000. Both the plasminogen activator and the Mr 105 000 esterase were shown to be glycoproteins by affinity chromatography on lentil lectin-Sepharose. These results indicate that the plasminogen activator of thymocytes is a glycosylated serine protease with an active site-containing subunit of Mr 105 000 which is specifically localized in the plasma membrane.
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PMID:Characterization of a plasma membrane-associated plasminogen activator on thymocytes. 679 69

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.
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PMID:Partial purification and characterization of a novel neutral proteinase from human uterine cervix. 699 9

A simple and sensitive indirect assay for quantifying plasminogen activator using [3H]-casein as substrate is described. The assay has been used to measure plasminogen activators from various sources including bacteria, cultured cells, and human plasma. The assay is linear with respect to concentration of plasminogen activator and time of incubation and is independent of concentration of plasminogen. The assay can routinely be used to quantify as few as 8 X 10(-3) international units ml-1 of streptokinase. Results obtained with the [3H]-casein assay correlate well with those obtained by the fibrin plate method (R = 0.83 by Spearman's ranked co-efficient of correlation). The reagents are extremely stable and easily stored. The ease with which the assay can be performed gives the clinical laboratory the potential to test large numbers of patients upon short notice and within a short period of time.
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PMID:Simple and sensitive assay employing stable reagents for quantification of plasminogen activator. 719 61


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