Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three natural proteinase isoinhibitors with low isoelectric points BUSI I A (pI = 3.9), BUSI I B1 (pI = 3.4 and BUSI I B2 (pI = 3.7) were isolated from bull seminal plasma by gel filtration on Sephadex G-50 and ion exchange chromatography on DEAE-Sephadex and SE-Sephadex. Isoinhibitors Bl and B2 have identical amino acid composition. Isoinhibitor A contains six amino acid residues less than isoinhibitors B1 and B2. Since sugars have been detected in the isoinhibitors, heterogeneity may also be due to the sugar component. The isoinhibitors show the same inhibitory properties; all of them inhibit acrosin, trypsin and chymotrypsin. Glandular kallikrein is also inhibited, but to a very low extent only. The molecular weight (Mr approximately 8 900) was determined by gel filtration.
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PMID:Isolation of acidic acrosin isoinhibitors (BUSI I A, BUSI IB1 and BUSI I B2) from bull seminal plasma. 39 5

Glandular kallikrein is known to promote contractions of the isolated, estrogenized rat uterus, perhaps independently of kinin formation. The recent availability of kinin receptor antagonists led us to study whether they might affect the oxytocic activity of kallikrein. DArg0-Hyp3-Thi5,8-DPhe7-bradykinin (8.5 x 10(-7) M) displaced the dose-response curves to both bradykinin (from 1.0 x 10(-9) to 4.0 x 10(-6) M) and kallikrein (from 4.7 x 10(-11) to 8.0 x 10(-9) M) approximately one order of magnitude to the right. This inhibition could not be due to a nonspecific effect on the uterine muscle, as the contractile response to oxytocin was not altered. In addition, carboxypeptidase B (a potent kininase) and kinin antibodies reduced the contractile response to kallikrein by 70 and 60%, respectively. Removal of the intervening agent restored the normal response. The effect of kallikrein depended on its enzymatic activity, inasmuch as kallikrein inactivated with D-Phe-Arg-Arg-CH2Cl was not oxytocic. Prolonged or multiple exposures to kallikrein completely abolished uterine response, whereas the effect of bradykinin was unaltered. Uterine horns rendered insensitive to kallikrein by prolonged exposure still contracted in response to trypsin. Kininogen was present in the uterine tissue in a concentration of 1.5 +/- 0.3 ng of bradykinin equivalents per mg wet wt. No more than 15.9 +/- 1.2% of this total was due to plasma contamination. Only 21.5 +/- 2.9% of total kininogen could be cleaved by kallikrein. We conclude that part of the oxytocic activity of kallikrein is related to generation of kinins from a kallikrein-sensitive kininogen present in the isolated rat uterus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinins contribute to the contractile effects of rat glandular kallikrein on the isolated rat uterus. 272 35

Glandular kallikrein (a trypsin-like serine protease) is a major estrogen-induced and dopamine-repressed protein in the rat anterior pituitary which appears to be associated with lactotrophs. In the pituitary the enzyme predominantly exists as a latent zymogen (pro-glandular kallikrein) which can be activated by trypsin. This study reports experiments employing biochemical techniques to investigate the subcellular localization of glandular kallikrein. Anterior pituitaries from estrogen-treated rats were fractionated on a discontinuous sucrose density gradient and the distribution of various organelles in the gradient was determined by conventional enzyme or protein marker assays. Each of the 8 organelle markers exhibited a unique distribution profile within the gradient. The distribution of glandular kallikrein was closely correlated (r = 0.91) with that of nucleoside diphosphatase (a marker for trans cisterna of the Golgi apparatus). For both glandular kallikrein and nucleoside diphosphatase, 35-45% of the total activity was found in Golgi zones of the gradient, and 18-22% was in the secretory vesicle fraction. In all of the subcellular fractions, 91-97% of the glandular kallikrein existed in the zymogen form (pro-glandular kallikrein). In Golgi fractions, 38% of the glandular kallikrein remained membrane-bound following freeze-thawing and two washes in hypotonic media; 94% of the nucleoside disphosphatase remained membrane-bound following such treatment. The results indicate that glandular kallikrein is most highly concentrated in trans cisternae of the Golgi apparatus with substantial activity also present in secretory vesicles. This localization is consistent with a role for glandular kallikrein as a prohormone processing enzyme in lactotrophs.
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PMID:Biochemical investigation of the subcellular localization of the estrogen-induced pro-glandular kallikrein in the rat anterior pituitary. 272 45

Glandular kallikrein is a major estrogen-induced protein of the rat anterior pituitary. A second kallikrein-like protease in the rat anterior pituitary (kallikrein A) is not affected by estrogens, nor is a third pituitary protease which cleaves a trypsin substrate but not kallikrein substrates. This study examined whether any of the pituitary proteases are regulated by dopaminergic mechanisms. Ovariectomized female rats were treated for 5-10 days with reserpine (a catecholamine depleting agent), haloperidol (a dopamine receptor blocker) or bromocriptine (a dopamine receptor agonist); some rats also received 1 or 2 micrograms estradiol benzoate every 48 h. Following activation of latent proteases with trypsin, anterior pituitary extracts were assayed for kallikrein activity before and after fractionation on DEAE-Sephadex to separate the two kallikrein-like proteases. Reserpine or haloperidol doubled glandular kallikrein levels in anterior pituitaries from estrogen-treated rats. Reserpine or haloperidol had little or no effect in the absence of estrogen (estrogen produced a 5- to 7-fold increase in glandular kallikrein in the absence of drug treatment). Bromocriptine markedly attenuated the ability of estrogen to induce glandular kallikrein. Further, bromocriptine blocked the ability of reserpine to increase glandular kallikrein levels, and haloperidol attenuated the effect of bromocriptine. Other anterior pituitary proteases were unaffected by either estrogen, haloperidol, reserpine or bromocriptine. The results demonstrate that the estrogen induction of glandular kallikrein in the rat anterior pituitary is modulated by inhibitory dopaminergic mechanisms. Prolactin is the only pituitary hormone which exhibits a similar profile of hormonal and neuroendocrine regulation; this suggests a possible link between glandular kallikrein and prolactin.
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PMID:Dopaminergic regulation of the estrogen-induced glandular kallikrein in the rat anterior pituitary. 302 15

Glandular kallikrein (a trypsin-like serine protease) is an estrogen-induced and dopamine-repressed protein in the rat anterior pituitary which appears to be associated with lactotrophs. This study examined glandular kallikrein levels in diethylstilbestrol (DES)-induced pituitary tumors in F344 rats and compared it to plasma and pituitary prolactin, and pituitary wet weight. Ovariectomized F344 rats were implanted with Silastic tubes containing 0 or 5 mg DES for 1, 3, 5, 7, or 9 weeks. Glandular kallikrein was measured by microenzymatic assay using D-valylleucylarginyl-p-nitroanilide following trypsin treatment of extracts to activate latent forms of glandular kallikrein. Prolactin was measured by radioimmunoassay. DES induced steady time-dependent increases in pituitary wet weight with 7- and 16-fold increases observed by 5 and 9 weeks, respectively. Growth rates averaged 11.4 mg/week during the first 5 weeks of DES exposure, and then increased to 23.2 mg/week between weeks 5 and 9. Glandular kallikrein total activity (nmol/min/pituitary) increased 130- and 240-fold after 3 and 5 weeks of DES exposure, respectively, and then abruptly plateaued. The specific activity (nmol/min/mg protein) of glandular kallikrein peaked at 3-5 weeks (36-fold increase compared to controls) and then declined as pituitary protein but not glandular kallikrein continued to increase. Total pituitary prolactin constantly rose during DES exposure with 12- and 26-fold increases after 5 and 9 weeks, respectively. Plasma prolactin levels also continuously rose during exposure to DES with 130- and 290-fold increases after 5 and 9 weeks, respectively. No major strain differences were found with regard to sensitivity to the acute effects of estrogen or dopaminergic stimulation on glandular kallikrein induction. DES-induced pituitary tumors in F344 rats are well known to arise via lactotroph proliferation, and the striking elevation in glandular kallikrein and prolactin during the early phases of tumor growth provide further support for a localization of glandular kallikrein in lactotrophs. However, the abrupt stabilization in glandular kallikrein levels by week 5 was unexpected and may signal a biochemical transformation of the tissue during tumor progression.
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PMID:Glandular kallikrein in estrogen-induced pituitary tumors: time course of induction and correlation with prolactin. 339 Aug 8

Glandular kallikrein (a trypsin-like serine protease) is a major estrogen-induced protein in the rat anterior pituitary, which appears to be associated with lactotropes. The present study examined glandular kallikrein levels in the anterior pituitary during the rat estrous cycle and pregnancy. After trypsin treatment of anterior pituitary homogenates (to activate latent forms of the enzyme), glandular kallikrein activity was measured by using the chromogenic substrate D-val-leu-arg-p-nitroanilide: 98-95% of the enzymatic activity was immunoprecipitable with glandular kallikrein antiserum. Glandular kallikrein levels did not change significantly during the various phases of the rat estrous cycle. However, a sharp decrease was observed starting on Day 15 of pregnancy and lasting through parturition; levels had almost returned to control values by Day 5 of lactation.
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PMID:Glandular kallikrein levels in the rat anterior pituitary during the estrous cycle and pregnancy. 367 89

Completely inactive renin was isolated from normal human plasma by DEAE-Sepharose column chromatography and Blue-Sepharose column chromatography. This inactive renin had a molecular weight of 54,000 daltons as determined by gel filtration on Ultrogel AcA 44. When the inactive renin was activated by trypsin, its molecular weight decreased to 48,000 daltons. The trypsin-activated renin differed from a native form of active renin in plasma with respect to molecular weight (active renin, 43,000), pI value (active renin, 5.20; trypsin-activated renin, 5.06), km value (active renin, 60 nmoles/liter; trypsin-activated renin, 89 nmoles/liter), Ki value for pepstatin A (active renin, 2.6 mumoles/liter; trypsin-activated renin 5.0 mumoles/liter) and pH profile for angiotensin formation. Glandular kallikrein (human urinary or pig pancreatic) did not activate the inactive renin. When the trypsin-activated renin was treated with glandular kallikrein, its activity was unchanged, but its molecular and kinetic properties except pI value (trypsin-activated kallikrein-treated renin, 4.82) coincided with those of a native form of active renin in plasma. These results indicate that glandular kallikrein does not directly activate inactive renin but participates in the activation process of inactive renin. The results also suggest that inactive renin in human plasma is a renin precursor.
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PMID:Role of glandular kallikrein in the activation process of human plasma inactive renin. 633 49