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)

Specific modification of the single lysine residue (Lys-12) in glucagon with O-methylisourea has been effected by blocking the reactivity of the amino terminal histidine with copper, providing a method for obtaining [12-homoarginine]glucagon. It was found that as a side reaction, under the conditions of the modification reaction, Cu(II) catalyzed cleavage of the polypeptide chain between Asp-9 and Tyr-10, and between Lys-12 and Tyr-13. This observation may be of value for development of a sequence-specific peptide cleavage procedure. The dilute solution conformations of glucagon and [12-homoarginine]-glucagon were compared by circular dichroism, fluorescence, phosphorescence, energy transfer, and optical detection of magnetic resonance. The results indicate that conversion of Lys-12 to homoarginine does not alter the helix content the side chain conformation in the vicinity of the tyrosine and tryptophan residues, or the relative distances and orientations between these residues. However, the modification reduces the hormone potency towards activation of lipolysis in isolated rat epididymal fat cells by a factor of seven. We attribute the loss of potency to an interference with a specific interaction between the lysine residue and the fat cell hormone receptor, and not to a change in the solution conformation of the hormone.
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PMID:[12-Homoarginine]glucagon: synthesis and observations on conformation, biological activity, and copper-mediated peptide cleavage. 42 94

Following elongation of spermatids in mammals, the histones are replaced by a set of basic nuclear transition proteins; in the rat there are four, named TP1-TP4. Of these, TP1 and TP2 are well characterized. Here we report the purification to homogeneity of TP4 from rat spermatids. It is a low molecular mass (about 13-20 kDa) basic protein with arginine and lysine constituting 24 mol % and histidine 2.2 mol %. Its 25 N-terminal amino acids were sequenced, and no sequence homologies with any known protein were found. Polyclonal antibodies raised against it in rabbit did not cross-react with other transition proteins, protamines, or histones. The presence of TP4 during sperm development was monitored by cell separation studies. No TP4 was detected in round spermatids, and along with TP1 and TP2, it is present in step 13-15 spermatids and its amount decreased in steps 16-19. Trace amounts of TP4 were also detected in epididymal sperm. A possible role for TP4 in spermatid and sperm chromatin structure is discussed.
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PMID:Purification and characterization of the rat spermatid basic nuclear protein TP4. 146 32

Metabolic potency of des-(B26-B30)-insulin-B25-amide, [TyrB25]des- (B26-B30)-insulin-B25-amide and [HisB25]des-(B26-B30)-insulin-B25-amide was studied in anaesthetized rats. Compared to insulin, full potency for des-(B26-B30)-insulin-B25-amide and an enhanced potency for both substituted analogues has been described previously on rat adipocytes in vitro. Hypoglycaemic effects following i.v. injection of all of these analogues were almost identical to those of native insulin with a half-maximal effective dose of approximately 3 nmol.kg-1. Stimulation of glucose metabolism during euglycaemic hyperinsulin-/analogueaemic clamp studies was indistinguishable from that of the native hormone with a maximal stimulation of approximately 19 mg.kg-1.min-1 and half-maximal effective hormone concentrations of approximately 1 pmol.ml-1. Analogue action on individual peripheral tissues estimated by the uptake of 2-deoxyglucose as well as stimulation of lipogenesis in epididymal fat was not different to that of insulin. These data demonstrate that C-terminal amidation of des-(B26-B30)-insulin results in a shortened molecule with full in vivo metabolic potency. When substituting phenylalanine in position B25 by tyrosine or histidine, the insulin-identical potency is preserved.
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PMID:In vivo metabolic activity of des-(B26-B30)-insulin-B25-amide and related analogues in the rat. 222 26

By using a chemically defined (protein-free) culture medium that supports sperm viability but not capacitation or the acrosome reaction, we have determined that hamster spermatozoa can be chemically capacitated in vitro by the divalent cation chelators D-penicillamine, L-histidine, and L-cysteine in the absence of bovine serum albumin (BSA). Washed cauda epididymal spermatozoa were preincubated (1-2 x 10(6) sperm/ml) for 3, 4, or 6 hr at 37 degrees C in 5% CO2 in air. The basic culture medium used for sperm preincubation and for sperm:egg coincubation was a modified Tyrode's solution (protein-free) containing 10 mM sodium lactate, 100 microM sodium pyruvate, and 1.0 mg/ml polyvinylalcohol (TLP-PVA). Sperm viability was maintained in all preincubation and coincubation media with PHE (20 microM D-penicillamine, 100 microM hypotaurine, and 1.0 microM epinephrine). The low control sperm preincubation medium consisted of TLP-PVA. In some cases the high control preincubation medium also contained 3 mg/ml BSA (TALP-PVA). The experimental preincubation medium was TLP-PVA with additional D-penicillamine (125 or 500 microM), or L-histidine (10, 100, or 1,000 microM) or L-cysteine (25, 75, or 125 microM). After preincubation, sperm were coincubated (2 x 10(4) sperm/ml) with cumulus-free hamster eggs in TALP-PVA +/- additional D-penicillamine, L-histidine, or L-cysteine for 1.5 hr, fixed, and evaluated for percent egg penetration as an index of sperm capacitation. The results demonstrate that hamster spermatozoa can be chemically capacitated in vitro with D-penicillamine (500 microM: range of mean penetration values, 53.6%-84.3%), L-histidine (100 microM: range of mean values, 24.8%-56.3%) or L-cysteine (75 microM: 51.3%) in the absence of exogenous protein.
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PMID:Capacitation of hamster spermatozoa with the divalent cation chelators D-penicillamine, L-histidine, and L-cysteine in a protein-free culture medium. 273 1

An ELISA for the detection of antibodies to Histophilus ovis was used to evaluate the association of epididymal lesions in rams with serologic response to His ovis. Comparison of ELISA results for His ovis in groups of rams with epididymal lesions with ELISA results of clinically normal rams (control group) revealed a significant difference (P less than 0.01) between the control group and those rams from which His ovis was isolated. A significant difference (P less than 0.01) was noticed between the control group and rams with lesions from which an organism other than His ovis or Brucella ovis was isolated. Additionally, a significant difference (P less than 0.01) was noticed in ELISA results between the control group and affected rams from which no organism was recovered and in which the epididymal lesion was not limited to the head of the epididymis. A difference was not detected in the His ovis ELISA results between control rams and rams with lesions associated with a B ovis infection or rams from which no organism was recovered and in which the epididymal lesion was limited to the head of the epididymis. The serologic findings in our study suggest that His ovis is more important in the development of epididymitis in rams than culture results alone would indicate.
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PMID:Serodiagnosis of Histophilus ovis-associated epididymitis in rams. 334 31

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

A comparison of the protein compositions of mouse late-step spermatids and cauda epididymal sperm has revealed that the relative distribution of the two amino acid sequence variants of mouse protamine differ markedly in spermatids and sperm. Sonication-resistant spermatids contain the two variants in a ratio of 1:1, while the ratio of these two proteins in cauda epididymal sperm is approx. 2:1. Labeling studies in vivo have shown that this difference is due, in part, to an asynchrony in the time of synthesis of the two protamine variants. Both proteins are synthesized in late-step spermatids, but synthesis of the tyrosine variant in sperm chromatin begins approximately one day before synthesis of the more predominant histidine variant. Analyses of the time of synthesis of protamine and the four transition proteins in late-step spermatids allowed us to estimate the spermatid stage in which these proteins are deposited on DNA and relate these events to the onset of sonication resistance in maturing spermatids. These results indicate that: (1) synthesis and deposition of protamine begins coincident with the onset of sonication resistance in early step 12 spermatids; (2) protamine deposition is complete by mid-step 15; and (3) synthesis of the transition proteins occurs coincident with protamine synthesis.
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PMID:DNA packaging in mouse spermatids. Synthesis of protamine variants and four transition proteins. 669 53

Persistent infertility after vasectomy reversal by vasovasostomy may be due to irreversible changes in epididymal physiology, producing morphologic abnormalities of the sperm tail. Specimens from 29 men with persistent infertility following vasectomy reversal were analyzed and sperm motility and morphology were evaluated. the percentage of motile sperm was below normal in 23 specimens. Swimming speed evaluation on 20 specimens showed only 4 were below the normal range. In 19 of the 29 specimens, 10% or more of the sperm cells examined were characterized by a normal head and a coiled or shortened tail. Within this group, the percentage of sperm with tail abnormalities ranged from 2-64%, with a mean of 18.1%. The appearance of sperm tail abnormalities in conjunction with normal or high sperm concentrations suggests a disturbance of epididymal physiology. The epididymal environment is required for the final maturation of spermatazoa and the acquisition of normal motility and fertilizing ability. The study results suggest that these epididymal functions may be impaired in some men after vasectomy. A case report of a 32 year old man who had a vasectomy 7 years prior to referral to the evaluation group, and a successful vasovasostomy 2 years prior, revealed only 20% of the sperm evaluated in the initial specimen had the normal head and tail shape. His semen volume was 3.5 ml with a sperm concentration of 250 million/ml. 25% of the sperm were motile. Reexamination of the semen 8 times during the next year showed no significant changes. The cervical mucus penetration test showed no abnormalities of the sperm-cervical mucus interaction. When the motile sperm were spearated from the immotile cells and incubated with zona-free hamster eggs, all of the eggs were penetrated. Attempts were unsuccessful to isolate sufficient numbers of motile cells for artificial insemination, however, a normal pregnancy was conceived 1 year after the initial evaluation without additional therapy. One other man from the group also produced a pregnancy. It is suggested that the morphologic abnormalities may not confer sterility on the affected individual even when present in the majority of sperm cells, as indicated by the ability of sperm with normal tails to fuse with zona-free hamster eggs in vitro.
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PMID:Abnormalities of sperm morphology in cases of persistent infertility after vasectomy reversal. 709 58

A new melanocyte-stimulating peptide has been isolated from acid extracts of frozen human pituitary glands by salt/ethanol fractionation, Sephadex G-75 gel filtration and DEAE- and cM-cellulose ion-exchange chromatography. The peptide is glycosylated, has an N-terminal tryptophan residue and an apparent mol.wt. of 16000 as estimated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Its amino acid analysis closely resembles residues Trp-105 to Gln-29 predicted for the common precursor protein of bovine corticotropin and beta-lipotropin by Nakanishi, Inoue, Kita, Nakamura, Chang, Cohen & Numa [(1979) Nature (London) 278, 423-427]. This fragment is expected to have melanotropin activity due to the tetrapeptide -His-Phe-Arg-Trp- (residues -51 to -48) of the predicted sequence of the common precursor. It was found to have a molar potency of 1 X 10(-5) relative to alpha-melanotropin in the frog skin bioassay. These characteristics are consistent with the isolated melanotropin peptide being a non-corticotropin, non-lipotropin peptide of the human common precursor protein of corticotropin and lipotropin. The peptide neither potentiates the adrenal weight-maintenance activity of corticotropin-(1-24)-tetracosapeptide when administered to hypophysectomized rats, nor stimulates release of non-esterified fatty acids from isolated rat epididymal cells. A second N-terminal-tryptophan glycopeptide was also isolated, which had an amino-acid composition similar to that predicted for the bovine common precursor protein, residues Trp-105 to Gly-35.
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PMID:Purification and characterization of a gamma-melanotropin precursor from frozen human pituitary glands. 747 89

At the end of spermiogenesis, sperm chromatin stabilization is ensured by protamine dephosphorylation and, in mammals, by the formation during epididymal transit, of intra- and inter-molecular disulfide bridges between protamines. In cuttlefish, the nuclear protein transition histones-->spermatid-specific protein T-->protamine Sp is very similar to that occurring in mammals during spermiogenesis. However, in cuttlefish, the protamine Sp is devoid of cysteine residues. The protein complement of cuttlefish epididymal sperm nuclei has been investigated. A minor basic protein, called protein E, has been isolated. Its primary structure was established from sequence analysis and mass spectrometry data of the protein and its fragments. Protein E contains a motif -Cys-Xaa2-Cys-Xaa23-His-Cys-Xaa2-Cys- which is likely to adopt a zinc finger conformation. Reduced protein E does fix zinc whereas alkylation of cysteine residues abolishes this ability. The sequence of protein E does not correspond to that of any known protein, but presents some similarities with a part of ZFY protein, a putative human transcription factor specifically expressed in germinal cells and which could be involved in spermatogenesis.
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PMID:Isolation and characterization of a small putative zinc finger protein from cuttlefish epididymal sperm cells. 812 4


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