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  • fertillization  (1)
  • heparin affinity  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Methods in cell science 10 (1986), S. 125-132 
    ISSN: 1573-0603
    Keywords: basic fibroblast growth factor ; heparin affinity ; hepatoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intact human hepatoma derived basic fibroblast growth factor (bFGF) is a cationic 18 400-molecular-weight polypeptide, which stimulates the proliferation of 3T3 and endothelial cells at 1 ng/ml. bFGF has a strong affinity for heparin, and can be purified to homogeneity from human hepatoma cells using heparin-Sepharose chromatography. A three-step procedure is used: (a) extraction of the cells with 1M NaCl at pH 7.5; (b) Bio-Rex 70 cation exchange chromatography; and (c) heparin-Sepharose chromatography. The molecular weight of bFGF depends on the pH of the cell extraction step. When extracted at neutral pH, intact bFGF is obtained with a molecular weight of 18 400, however when extracted at pH 3.5 to 4.5 the molecular weight of bFGF is about 16 500. Lowering the molecular weight by acid pH extraction can be inhibited with a mixture of the proteinase inhibitors, PMSF, leupeptin, and pepstatin. These results suggest that degradation of bFGF is the result of cleavages by acid proteinases. It has been determined by amino acid sequence data and western blot analysis that the cleavages occur at the amino terminus of bFGF. The lower molecular weight form of bFGF has the same biological activity and exhibits the same chromatographic behavior on heparin-Sepharose as does intact bFGF.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 12 (1985), S. 101-116 
    ISSN: 0148-7280
    Keywords: fertillization ; spermatozoon ; gamete interaction ; zona pellucida ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In order to identify those proteins from the plasma membrane of hamster spermatozoa that exhibit an affinity for components of the zona pellucida we have used the Western blot technique. Zonae pellucidae from postovulatory hamster oocytes were solubilized by exposure to an acidic pH and then radiolabeled using the Bolton-Hunter reagent. These 125I-zona pellucida proteins retain their immunoreactivity and migrate in three heterogeneous bands when submitted to SDS-PAGE electrophoresis. Membrane proteins from epididymal spermatozoa of mature hamsters were extracted by treatment with Nonidet P-40 and then submitted to electrophoresis (SDS-PAGE). The proteins in the gel were electrophoretically transferred to a nitrocellulose membrane and then probed with the radiolabelled zone pellucida proteins. 125I-zona pellucida proteins bind preferentially to a sperm protein with a molecular weight of 26,400 ± 1,400 daltons (n = 9). Using a similar procedure it was shown that this protein also binds 125I-Concanavalin A. The interaction between the sperm protein and the 125I-zona pellucida proteins shows species specificity as demonstrated by the fact that the hamster 125I-zona pellucida proteins do not bind to proteins extracted from ram, bull, and stallion spermatozoa. Whether this sperm protein could be implicated be implicated in the process of sperm-egg interaction is under investigation.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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