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Query: UMLS:C1519176 (PSA)
 5,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The three-dimensional structures of the bacterial serine proteases SGPA, SGPB, and alpha-lytic protease have been compared with those of the pancreatic enzymes alpha-chymotrypsin and elastase. This comparison shows that approximately 60% (55-64%) of the alpha-carbon atom positions of the bacterial serine proteases are topologically equivalent to the alpha-carbon atom positions of the pancreatic enzymes. The corresponding value for a comparison of the bacterial enzymes among themselves is approximately 84%. The results of these topological comparisons have been used to deduce an experimentally sound sequence alignment for these several enzymes. This alignment shows that there is extensive tertiary structural homology among the bacteria and pancreatic enzymes without significant primary sequence identity (less than 21%). The acquisition of a zymogen function by the pancreatic enzymes is accompanied by two major changes to the bacterial enzymes' architecture: an insertion of 9 residues to increase the length of the N-terminal loop, and one of 12 residues to a loop near the activation salt bridge. In addition, in these two enzyme families, the methionine loop (residues 164-182) adopts very different comformations which are associated with their altered substrate specificities.
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PMID:Amino acid sequence alignment of bacterial and mammalian pancreatic serine proteases based on topological equivalences. 9 20

Zona induced acrosome reaction of human spermatozoa was examined by FITC labelled PSA staining. When human spermatozoa were incubated with salt stored human eggs for 6 hours, the percentage of acrosome reacted spermatozoa was 35.7 +/- 17.7%. The zona induced acrosome reaction rate was significantly higher than that of the spontaneous acrosome reaction (2.8 +/- 1.9%). These date indicate that the zona pellucida of the human egg have the ability to induce the acrosome reaction as in other mammalian zona. Additionally the effect of cervical mucus on the acrosome reaction was examined. Spermatozoa which passed through the cervical mucus were collected and examined for the rate of spontaneous and zona induced acrosome reaction. The rate of spontaneous acrosome reaction was almost the same as the control, but the rate of zona induced acrosome reaction (51.6 +/- 6.8%) was significantly higher than that of the control (25.6 +/- 9.4%). These data suggest that spermatozoa appear to complete capacitation by passing through cervical mucus.
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PMID:[Effect of cervical mucus on zona induced acrosome reaction of human spermatozoa]. 160 53

Cryostat sections from rat gracilis muscles were incubated with different biotinylated lectins: Con A (Concanavilin A), WGA (Wheat germ agglutinin), SBA (soybean agglutinin), GS I and GS II (Griffonia simplicifolia agglutinin), LCA (Lens culinaris agglutinin), PNA (peanut agglutinin) and PSA (Pisum sativum agglutinin). The sections were subsequently treated with alkaline phosphatase conjugated avidin. The lectin binding sites were visualized after incubation in substrate media containing: (1) 5-bromo-4-chloro indoxyl phosphate and Nitro Blue tetrazolium or copper sulphate; (2) naphthol AS-MX phosphate or naphthol AS-BI phosphate and various types of diazonium salts; (3) alpha-naphthylphosphate and Fast Blue BB; (4) beta-glycerophosphate according to the method of Gomori. The results obtained with the alkaline phosphatase methods were compared with those seen with a streptavidin-horseradish peroxidase procedure. Several chromogen protocols for visualizing alkaline phosphatase activity showed differences in the ability to detect lectin binding sites. A sarcoplasmic reaction was evident for Con A, GS II, WGA, LCA, and PSA after incubation in the indoxyl phosphate medium. Sarcoplasmic reaction for GS II was also noticed after incubation with naphthol AS-MX Fast Blue BB and beta-glycerophosphate. The latter substrate also gave rise to a sarcoplasmic Con A reaction. With the indoxylphosphate tetrazolium salt method some muscle fibres showed a very strong intracellular reaction after incubation with Con A and GS II while the staining intensity was weak in other fibres. The same muscle fibres were stained with PAS. No sarcoplasmic reactions were observed with either naphthol phosphate media or with the diaminobenzidine peroxidase methods. Further, the staining of the muscle fibre periphery, connective tissue, an capillaries was intensified using the indoxyl method. The indoxylphosphate-tetrazolium salt method seems to be suitable for future investigations of lectin binding sites in muscle sections.
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PMID:Lectin binding in skeletal muscle. Evaluation of alkaline phosphatase conjugated avidin staining procedures. 171 10

The objective of this prospective study was to evaluate the specificity of human sperm/zona pellucida interaction under hemizona assay (HZA) conditions in experiments with gametes from the same and different species. Human, cynomolgus monkey and hamster oocytes were used after salt-storage. Oocytes were bisected into matching hemizonae by micromanipulation and used in the HZA. Semen was obtained from healthy men (donors) and male cynomolgus monkeys and prepared by wash and swim-up. Sperm binding to matching hemizonae was assessed (tight binding) after 4-h coincubation in the HZA in homologous and interspecies experiments. Acrosome reaction was evaluated in the sperm droplets using FITC-PSA and on the hemizonae using the T-6 monoclonal antibody. On human hemizonae, the number of tightly bound sperm for human and monkey were 93.2 +/- 15.8 and 3.9 +/- 1.3, respectively (P < 0.001). On monkey hemizonae, the number of tightly bound sperm for monkey and human were 126.0 +/- 34.8 and 2.8 +/- 1.6, (P = 0.02) respectively. On hamster hemizonae, there was negligible binding of human and monkey sperm. There was a significantly higher incidence of acrosome reacted sperm on the zona pellucida in homologous compared to heterologous experiments. These results demonstrate a high species-specificity of human gamete functions under HZA conditions, providing further support for the use of this bioassay in infertility and contraception testing.
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PMID:The specificity of human spermatozoa/zona pellucida interaction under hemizona assay conditions. 850 81

It has previously been shown that when boar spermatozoa are incubated in a modified Krebs-Ringer bicarbonate (mKRB), head-to-head agglutination occurs in many cells. The aim of the present study was to investigate the effects of cyclic adenosine 3',5'-monophosphate (cAMP) and serum albumin on sperm agglutination and to discuss a possible mechanism for sperm agglutination. Spermatozoa were collected from four mature boars, washed and incubated in mKRB. After a 1-h incubation, a sample of each sperm suspension was smeared gently on a separate glass slide, dried and stained in a phosphate-buffered solution of Giemsa to assess the percentage of head-to-head agglutinated cells in each suspension. In the samples incubated in mKRB, approximately 50% of the spermatozoa were agglutinated with one another at the acrosome. However, the percentages of head-to-head agglutinated spermatozoa were greatly reduced by a lack of calcium chloride in mKRB, but were recovered by the addition of dibutyryl cAMP (dbcAMP, a cAMP analogue) in a dose-dependent manner between 1 and 1000 microM. Addition of 3-isobutyl-1-methylxanthine (IBMX, 100 and 500 microM) instead of dbcAMP also significantly increased the percentages of head-to-head agglutinated spermatozoa. Moreover, the effects of adding dbcAMP were attenuated by treatment with Rp-adenosine 3',5'-cyclic monophosphorothioate triethylamine salt (0.25-1.0 mM, a cAMP antagonist) or H-89 (5 microM, a protein kinase-A inhibitor), but were enhanced by treatment with okadaic acid (500 nM) and calyculinA (500 nM) (inhibitors of protein serine/threonine phosphatase). In sperm samples incubated in mKRB containing 0.1% polyvinyl alcohol (mKRB-P) or mKRB-P lacking calcium chloride and supplemented with 1 mM dbcAMP, a lack of bovine serum albumin (BSA) resulted in a significant decrease in the percentages of head-to-head agglutinated spermatozoa. Addition of porcine serum albumin (PSA, 1-4 mg mL(-1)) or methyl-beta-cyclodextrin (MBC, 5-10 mg mL(-1)) instead of BSA was as effective as BSA (4 mg mL(-1)) in enhancing sperm agglutination. However, the effects of BSA (4 mg mL(-1)) or MBC (5 mg mL(-1)) were reduced by pre-mixing these reagents with cholesterol 3-sulfate (a cholesterol analogue, 5 microg mL(-1) for BSA and 375 microg mL(-1) for MBC). In addition, a protein 'anti-agglutinin' inhibiting sperm agglutination, was extracted from spermatozoa incubated with serum albumin or MBC and detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting techniques. The obtained Western blots revealed that sperm-bound anti-agglutinin was detected less in the samples incubated with either BSA (4 mg mL(-1)) or MBC (5-10 mg mL(-1)), compared with control samples. Moreover, pre-mixing MBC (5 mg mL(-1)) with cholesterol 3-sulfate (375 microg mL(-1)) reduced this reagent's effects on the loss of sperm-bound anti-agglutinin. Additionally, the assay of sperm agglutination and a chlortetracycline staining assay revealed that the percentages of head-to-head agglutinated spermatozoa were positively correlated with those of spermatozoa classified into B pattern (capacitated spermatozoa). These results are consistent with the following suggestions: (i) an adenylyl cyclase-cAMP-protein kinase system mediates a signalling pathway leading to head-to-head agglutination; and (ii) loss of anti-agglutinin from the spermatozoa may be modulated by changes in the plasma membrane induced by actions of serum albumin or MBC contained in a medium.
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PMID:Role of cyclic adenosine 3',5'-monophosphate and serum albumin in head-to-head agglutination of boar spermatozoa. 1145 Oct 22

Prostate specific antigen (PSA, also known as human kallikrein 3) is an important diagnostic indicator of prostatic disease. PSA exhibits low protease activity (>10(4)-fold less than chymotrypsin) under the usual in vitro assay conditions. In addition, PSA does not react readily with prototypical serine protease inactivators. We expressed human PSA (rh-PSA) in Escherichia coli and have demonstrated that rh-PSA has properties similar to those of native PSA isolated from human seminal fluid. Both PSA and rh-PSA are >10(3)-fold more active in the presence of 1.3 M Na(2)SO(4). This activation is anion-dependent, following the Hofmeister series when normality is considered: SO(4)(2)(-) approximately citrate > Ac(-) > Cl(-) > Br(-) > I(-). The nature of the cation has little effect on salt activation. The rate of inactivation of rh-PSA by DFP is 30-fold faster in the presence of 0.9 M Na(2)SO(4), and the rate of inactivation by Suc-Ala-Ala-Pro-Phe-CK is >20-fold faster under these conditions. Azapeptides containing Phe or Tyr at position P(1) also inactivate rh-PSA in the presence of high salt concentrations. These compounds represent the first described inhibitors designed to utilize the substrate binding subsites of PSA. CD spectroscopy demonstrates that the conformation of rh-PSA changes in the presence of high salt concentrations. Analytical ultracentifugation and dynamic light scattering indicate that PSA remains monomeric under high-salt conditions. Interestingly, human prostatic fluid contains as much as 150 micro mol citrate/g wet weight, which suggests that salt concentrations may regulate PSA activity in vivo.
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PMID:Modulation of recombinant human prostate-specific antigen: activation by Hofmeister salts and inhibition by azapeptides. Appendix: thermodynamic interpretation of the activation by concentrated salts. 1157 Aug 74

Poly(sodium acrylate) (PSA) can be degraded by consortia of several bacterial species. We investigated the degradation mechanism for PSA (average molecular weight, 2100) by consortium no. L7-98. PSA was used as the sole carbon source in a mineral salt medium. After cultivation, the PSA had a range of molecular weights, including low-molecular-weight compounds, which were purified by gel-permeation and reversed-phase column chromatography. One purified compound, B1, with the molecular weight of 200, had a carbonyl group next to the terminus, according to 1H and 13C nuclear magnetic resonance spectrometry and X-ray analysis of the crystal structure. Two categories of metabolites of PSA were detected in the culture by electrospray ionization mass spectrometry. Results of high-resolution mass spectrometry (HR-MS) suggested that one kind of compounds had a carbonyl group and that the other kind of compounds had an aldehyde group and a double bond. Compounds having the molecular weights of 200 and 272 were rapidly produced from an acrylic acid oligomer with the molecular weight of 258 by resting cells of the consortium. HR-MS showed that a methylene group at the terminal unit was oxidized to a carbonyl group and that the compound with the molecular weight of 200 was compound B1. From these results, we propose that the degradation pathway of PSA involves (i) oxidation of a methylene group to a carbonyl group next to the terminus, (ii) decarboxylation to form an aldehyde group and dehydrogenation to form a double bond between the terminal unit and the next unit, and (iii) oxidation of the aldehyde group to a carboxyl group followed by elimination of an acetic acid.
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PMID:Mechanism for degradation of poly(sodium acrylate) by bacterial consortium no. L7-98. 1623 44

Human tissue kallikrein 4 (hK4) belongs to a 15-member family of closely related serine proteinases. hK4 is predominantly expressed in prostate, activates hK3/PSA, and is up-regulated in prostate and ovarian cancer. We have identified active monomers of recombinant hK4 besides inactive oligomers in solution. hK4 crystallised in the presence of zinc, nickel, and cobalt ions in three crystal forms containing cyclic tetramers and octamers. These structures display a novel metal site between His25 and Glu77 that links the 70-80 loop with the N-terminal segment. Micromolar zinc as present in prostatic fluid inhibits the enzymatic activity of hK4 against fluorogenic substrates. In our measurements, wild-type hK4 exhibited a zinc inhibition constant (IC50) of 16 microM including a permanent residual activity, in contrast to the zinc-independent mutants H25A and E77A. Since the Ile16 N terminus of wild-type hK4 becomes more accessible for acetylating agents in the presence of zinc, we propose that zinc affects the hK4 active site via the salt-bridge formed between the N terminus and Asp194 required for a functional active site. hK4 possesses an unusual 99-loop that creates a groove-like acidic S2 subsite. These findings explain the observed specificity of hK4 for the P1 to P4 substrate residues. Moreover, hK4 shows a negatively charged surface patch, which may represent an exosite for prime-side substrate recognition.
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PMID:Crystal structures of human tissue kallikrein 4: activity modulation by a specific zinc binding site. 1695 Mar 94

Biological hydrogels consisting of self-assembling peptide nanofibers are potentially excellent materials for various controlled molecular release applications. The individual nanofiber consists of ionic self-complementary peptides with 16 amino acids (RADA16, Ac-RADARADARADARADA-CONH(2)) that are characterized by a stable beta-sheet structure and undergo self-assembly into hydrogels containing approximately 99.5% w/v water. We report here on the diffusion properties of phenol red, bromophenol blue, 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (pyranine, 3-PSA), 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (4-PSA), and Coomassie Brilliant Blue G-250 (CBBG) through RADA16 hydrogels. The apparent diffusivity (D ) of phenol red (1.05+/-0.08 x 10(-10) m(2) s(-1)) is higher than that of 3-PSA (0.050+/-0.004 x 10(-10) m(2) s(-1)) and 4-PSA (0.007+/-0.002 x 10(-10) m(2) s(-1)). The difference in 3-PSA and 4-PSA diffusivities suggests that the sulfonic acid groups directly facilitate electrostatic interactions with the RADA16 fiber surface. Bromophenol blue and CBBG were not released from the hydrogel, suggesting that they interact strongly with the peptide hydrogel scaffold. The diffusivities (D ) of the dyes decreased with increasing hydrogel peptide concentration, providing an alternate route of controlling release kinetics. These results indicate that release profiles can be tailored through controlling nanofiber-diffusant molecular level interactions.
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PMID:Slow release of molecules in self-assembling peptide nanofiber scaffold. 1696 96

5-Methyltetrahydrofolate, (R)-flurbiprofen; Ad5CMV-p53, adalimumab, alefacept, alemtuzumab, Alequel, alicaforsen sodium, almotriptan, anakinra, aprepitant, aripiprazole, armodafinil; Bevacizumab, bortezomib, bosentan; Canfosfamide hydrochloride, ciclesonide, clofarabine, Cypher; Darbepoetin alfa, diclofenac potassium, drotrecogin alfa (activated), duloxetine hydrochloride; Eel calcitonin, eletriptan, eplerenone, everolimus, ezetimibe; Frovatriptan; Gefitinib, gamma-hydroxybutyrate sodium; HKI-272, HYB-165; Ibutamoren mesylate, imatinib mesylate, interleukin-21, ixabepilone; KRN-951; L-Arginine hydrochloride, levodopa/carbidopa/entacapone; Micafungin sodium, motexafin gadolinium, mycophenolic acid sodium salt; Nesiritide; Peginterferon alfa-2a, pitavastatin calcium, pralatrexate, pregabalin, pVAX/L523S-Ad.L523S; Rasagiline mesylate, recombinant human nerve growth factor, regadenoson, rF-PSA, rimonabant, rizatriptan, rofecoxib, rosuvastatin calcium, rV-B7.1, rV-PSA; Sipuleucel-T, sirolimus-eluting stent, solifenacin succinate, sorafenib, sunitinib malate; Talactoferrin alfa, Taxus, tegaserod maleate, teriparatide, tipifarnib; Valdecoxib, vandetanib, vatalanib succinate; WT1-peptide vaccine; Xaliproden hydrochloride. (c) 2006 Prous Science. All rights reserved.
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PMID:Gateways to clinical trials. 1720 Jul 30


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