Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clusterin is a protein present in the rete testis fluid of the ram that elicits aggregation of erythrocytes and Sertoli cells in vitro. In view of its possible biologic function in relation to cell-cell interaction in the testis, we isolated this protein from ram rete testis fluid using sequential high-performance liquid chromatography columns and performed a detailed physicochemical characterization. This protein consists of two molecular variants designated form I and form II clusterin. Each form of clusterin consists of two subunits with an apparent molecular weight of 40,000. It is of note that the two subunits have no homology in their N-terminal amino acid sequences. However, the N-terminal amino acid pairs of the two subunits derived for the two forms of clusterin are identical. Using o-phthalaldehyde to block the Lys residue at the fourth amino acid pair from the N-terminus which leaves the Pro residue free for subsequent Edman degradation, we have deduced the N-terminal sequence of each of the two subunits for form I clusterin. Comparison of the NH2-terminal sequences of the two subunits of clusterin with the release 10.0 of the protein sequence data base of the Protein Identification Resource indicated no homology between either of the subunits of clusterin and any of the known proteins in the data base. A highly specific radioimmunoassay developed for clusterin was used to measure its concentrations in the fluids of the rete testis and cauda epididymis. Since a significant amount of immunoreactive clusterin was found in serum, the protein was partially purified from this source by immunoaffinity chromatography. Immunoreactive serum clusterin was smaller than the testicular clusterin (Mr 37,000 vs 40,000), but both proteins share common epitopes as demonstrated by radioimmunoassay and immunoblots. However, serum clusterin does not possess the biologic activity of the testicular clusterin in that it does not elicit cell aggregation in vitro. It is of note that deglycosylation of testicular clusterin can also eliminate this in vitro biologic activity, suggesting that the serum clusterin might be a deglycosylated form of the testicular protein and the carbohydrate core plays an important role in determining the cell aggregation activity. Studies on the distribution of this protein in the reproductive compartment indicate that it is highly concentrated in the rete testis and the cauda epididymal fluids. This suggests that this protein might have some important functions in the reproductive tract.
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PMID:Structural analysis of clusterin and its subunits in ram rete testis fluid. 341 74

The relationship between structure and activity of acid-extracted and purified acrosin obtained from cauda epididymal hamster spermatozoa was studied. A four-step purification procedure of acrosin was used; it included 1.) acid extraction, 2.) gel filtration over Sephadex G-100 resin, 3.) ion exchange on CM-Sepharose CL-6B, and 4.) affinity chromatography on proflavin-Sepharose 4B. Analysis of the purified enzyme by high-performance liquid chromatography (300 SW + I-125) revealed a molecular weight of 44,000, which was identical to that obtained for acid-extracted acrosin. Slab-gel electrophoresis under nondenaturing conditions showed only one active band, as revealed with a highly sensitive assay using N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester as substrate. The radiation inactivation size of acid extracted acrosin was calculated to be 8400. This small unit could represent the active polypeptide portion of a larger monomer molecule or could represent the size of active subunits. Because acrosin is autocatalytic and highly active during fertilization, it is suggested that the active portion of the completely processed form of the enzyme is of small molecular weight.
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PMID:Radiation inactivation of hamster acrosin reveals that the biologically active unit is of low molecular size. 347 95

Lipoprotein lipase activity was measured in an acetone-dried-powder preparation from rat epididymal adipose tissue using pig serum or pig serum lipoprotein, which had been chemically modified, as activator. Modification of acidic amino acids of lipoproteins with NN-dimethyl-1,3-diamine resulted in a complete loss of ability to activate lipoprotein lipase. Modification of 34% of lipoprotein arginine groups with cyclohexanedione resulted in the loss of 75% of the activation of lipoprotein lipase; approx. 42% of the original activity was recovered after reversal of the modification. This effect was dependent on the cyclohexanedione concentration. Modification of 48% of lipoprotein lysine groups with malonaldehyde decreased the maximum activation by 20%, but three times as much lipoprotein was required to achieve this. Non-enzymic glycosylation of lipoprotein with glucose, under a variety of conditions resulting in up to 28 nmol of glucose/mg of protein, had no effect upon the ability to activate lipoprotein lipase. In contrast non-enzymic sialylation resulted in a time-dependent loss of up to 60% of ability to activate lipoprotein lipase. Reductive methylation and acetoacetylation of serum did not affect the ability to activate lipoprotein lipase. The results are compared to the effects of similar modifications to low density lipoproteins on receptor-mediated endocytosis.
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PMID:The effects of chemically modifying serum apolipoproteins on their ability to activate lipoprotein lipase. 359 62

Clusterin, a glycoprotein that elicits cell aggregation, has previously been isolated from ram rete testis fluid, and has been partially characterized. In experiments reported, we have used monoclonal antibodies against clusterin in combination with indirect immunofluorescence microscopy to investigate the distribution of clusterin in the adult ram testis, rete testis, and excurrent ducts. Tissue blocks (5 mm3) were fixed in periodate/lysine/paraformaldehyde containing 0.1% glutaraldehyde and, after embedding, 5-microM sections were prepared for immunolocalization. In the testis, 2 basic patterns were observed: 1) strong to moderate staining for clusterin in the adluminal region with little staining in the basal region of the seminiferous epithelium and germinal cells; and 2) moderate staining throughout the seminiferous epithelium between germinal cells. In the rete testis, strong clusterin staining was localized intracellularly in the rete epithelial cells, most often associated with the luminal surface. In the epididymis, intracellular clusterin was localized in some principal cells of the caput epididymidis. The luminal surfaces and spermatozoa within the lumen were strongly positive. In the vas deferens, clusterin staining was associated with the luminal surface only. The presence of clusterin was clearly detected in unwashed isolated epididymal spermatozoa, but not in spermatozoa washed with phosphate-buffered saline containing 0.05% Tween 20.
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PMID:Immunolocalization of clusterin in the ram testis, rete testis, and excurrent ducts. 390 51

Binding sites for Con A and WGA were detected on bovine spermatozoa during epididymal maturation. We used colloidal gold as an EM-marker. The spermatozoa were treated according to a two-step method for lectin and colloidal gold, then adsorbed to lysine-coated nickel grids and subsequently examined by TEM in toto. Using this method we rapidly got information about the topographic distribution of lectin-binding sites. Major differences exist for WGA between caput and cauda spermatozoa. Conceding that cell-thickness poses some limitation, we consider this method to be practical and especially useful in studies concerning topographic distribution of cell surface components in single cell systems.
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PMID:Con A- and WGA-binding sites on bovine epididymal spermatozoa: TEM of specimens in toto. 623 81

Insulin from an elasmobranch, the spiny dogfish (Squalus acanthias) has been purified to near homogeneity by means of acid-ethanol extraction and salt precipitation. The amino acid sequences of the performic-acid-oxidised A and B chains have been determined and exhibit some unusual features. The A chain contains a total of 22 amino acids; only the insulin from coypu (a member of the Rodentia suborder, Hystricomorpha), has previously been reported to contain an extension past the A21 asparagine. The B10 histidine, which is involved in the formation of the insulin hexamers in higher vertebrates through the co-ordination of zinc, is present in this elasmobranch insulin. Several substitutions relative to bovine insulin occur in the proposed receptor binding region (A5Gln leads to His, B21Glu leads to Pro, B22Arg leads to Lys, B25Phe leads to Tyr). In spite of these substitutions, the maximal response in the rat epididymal fat cell assay is the same for bovine and dogfish insulins; the concentration required to produce the half-maximal response is, however, approximately threefold greater for dogfish insulin than that of bovine insulin. The use of interactive computer graphics model-building predicts that the dogfish insulin can attain a three-dimensional structure very similar to that of bovine insulin; circular dichroic spectra are presented which support the model-building studies.
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PMID:Dogfish insulin. Primary structure, conformation and biological properties of an elasmobranchial insulin. 635 61

The 600-MHz proton spectrum of dethiobiotin (prepared from d-biotin with Raney nickel) was measured in order to gain information pertaining to its stereochemical homogeneity. The spectrum demonstrated clearly that the material is a 6:1 mixture of two stereoisomers. The cis compound, corresponding to the stereochemistry of d-biotin, is the major isomer. Two biotinyl- and two dethiobiotinylinsulins were prepared in which the distance between the biotins and insulin was varied by interposition of spacer arms. The synthesis of these compounds involved repeated N-hydroxysuccinimido ester condensations. Biotin N-hydroxysuccinimido ester, dethiobiotin N-hydroxysuccinimido ester, 6-aminohexanoic acid, and N-[3-[(3-aminopropyl)carboxyamino]-propyl]succinamic acid N-tert-butyl ester served as the building blocks for the spacers. The latter compound was prepared from N-[3-[(3-aminopropyl)amino]propyl]succinamic acid sulfate by the use of a selective amino-protecting method based on the differential stability toward acid of citraconyl and tert-butoxycarbonyl amino-protecting groups. The structure of N-[3-[(3-aminopropyl)amino]propyl]succinamic acid sulfate was established unequivocally by X-ray diffraction. The attachment of the biotinylated spacers to the insulin was exclusively at the N alpha, B1 position. Homogeneity of the final products as well as of the intermediates used in their synthesis was established by thin-layer chromatography, by high-pressure liquid chromatography, and in most instances by elemental analysis. The ratio of 6-aminohexanoic acid to lysine in hydrolysates of the insulin derivatives was in agreement with theory. The insulin derivatives were required for a study on the effect of avidin on their ability to interact with insulin receptors on rat epididymal adipocytes, which is described in the accompanying paper.
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PMID:Syntheses of biotinylated and dethiobiotinylated insulins. 638 May 70

The triazine dyes, Cibacron blue F3GA and Procion red HE3B inhibited diaphorase activity of ferredoxin-NADP+ reductase, in a competitive manner with respect to NADPH. The Ki values were 1.5 and 0.2 microM, respectively. Binding of the dyes to the flavoprotein, as measured by difference spectroscopy, indicated an apparent stoichiometry of 1 mol dye/mol reductase and was prevented by NADP+ or high ionic strength. Chemical modification of a lysine residue and a carboxyl group at the NADP(H) binding site of the enzyme prevented complex formation with Procion red. Procion red showed a higher affinity for ferredoxin-NADP+ reductase than Cibacron blue. The Kd values were 1.9 and 5 microM, respectively. Once covalently linked to a Sepharose matrix, the triazine compounds specifically bind the flavoprotein. The interaction is partially electrostatic and partially hydrophobic. The enzyme can be eluted by high concentrations of salt or low concentrations of the corresponding coenzyme. The use of this affinity column allows the rapid purification of ferredoxin-NADP+ oxidoreductase from spinach leaves with good yields.
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PMID:Interaction of ferredoxin-NADP+ oxidoreductase with triazine dyes. A rapid purification method by affinity chromatography. 682 90

The effect of amino acids on insulin responsiveness in epididymal adipose tissue was examined. It was found that insulin-stimulated glucose oxidation in fat cells was significantly inhibited by glycine, alanine, valine, leucine, isoleucine, cysteine, methionine, lysine, phenylalanine, and proline. The effect of insulin on glucose incorporation into triglyceride is also severely diminished by these amino acids. In addition, alanine reduced the incorporation of precursors ([U-14C]glucose or [1-14C]palmitate) into triglyceride both in vitro and in vivo. The Ki values of alanine were 0.4 and 0.5 mM toward the precursors of glucose and palmitate, respectively. The mechanism of reduction of insulin responsiveness in rat adipose tissue is discussed on the basis of these results.
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PMID:Effect of amino acids on insulin-stimulated glucose metabolism in fat cells. 701 47

A trypsin-like protease was extracted with 1% cetyltrimethylammonium bromide (CTAB) at pH 7.0 from boar cauda epididymal sperm nuclei whose acrosin had previously been removed by acid extraction. The CTAB-extracted sperm protease (CSP) was purified by ion-exchange chromatography on CM-23, gel filtration on Sephadex G-100, affinity chromatography on benzamidine-CH-Sepharose 4B, and HPLC on CM-5PW. CSP is a two chain protein composed of M(r) 2.6K and M(r) 37K chains, which are covalently cross-linked by disulfide bonds. CSP exhibited a pH optimum between pH 8.0 and 9.0, and was inhibited by diisopropyl phosphorofluoridate, antipain, leupeptin, and 1-chloro-3-tosylamide-7-amino-L-2-heptanone. The activity of CSP was enhanced about 1.2-fold with 50 mM CaCl2, with which acrosin is enhanced 2.0-fold. The catalytic efficiency (kcat/Km) of CSP toward Bz-L-Arg-OEt, Tos-L-Arg-OMe, and Tos-L-Lys-OMe in the presence of 50 mM CaCl2 differed from that of acrosin by factors of 0.53, 1.2, and 0.80, respectively. Amino acid sequencing of V8-digested peptides of CSP, and its L- and H-chains showed that the amino acid sequence of CSP was closely related to, but different from, that of acrosin. These results suggest that CSP is a novel acrosin-like enzyme that differs from acrosin in its location in the sperm head, the effect of calcium ions on its activity, and its substrate specificity.
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PMID:Purification and characterization of a novel acrosin-like enzyme from boar cauda epididymal sperm. 782 68


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