Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Little is yet known about the biological and biochemical properties of the disintegrin-like domains of ADAM (a disintegrin and metalloprotease) proteins. Mouse ADAM 2 (mADAM 2; fertilin beta) is a sperm surface protein involved in murine fertilization. We produced recombinant proteins containing the disintegrin-like domain of mADAM 2 in both insect cells and in bacteria. The protein produced in insect cells (baculo D+C) contained a signal sequence followed by the disintegrin-like and cysteine-rich domains; it was purified from the medium of recombinant baculovirus-infected cells. A bacterial construct containing the disintegrin-like domain was produced in Escherichia coli as a glutathione S-transferase chimera. Baculo D+C, as well as the D domain of the bacterial construct (released with thrombin), bound to the microvillar surface of murine eggs. Using concentrations in the range of 1 to 5 microM, both recombinant proteins strongly inhibited sperm-egg binding and fusion; the baculovirus-produced protein exhibited a somewhat greater extent of inhibition (approximately 75 versus approximately 55% maximal inhibition). Substitution of alanine for each of the five charged residues within the disintegrin loop of mADAM 2 revealed a critical importance for the aspartic acid at position nine. Binding of both recombinant proteins to the egg was inhibited by the function blocking anti-alpha(6) monoclonal antibody, GoH3, but not by a nonfunction-blocking anti-alpha(6) monoclonal antibody. Binding was also inhibited by a peptide analogue of, and with an antibody against, the disintegrin loop of mADAM 2.
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PMID:Sequence-specific interaction between the disintegrin domain of mouse ADAM 2 (fertilin beta) and murine eggs. Role of the alpha(6) integrin subunit. 1076 72

SERPINE2, one of the potent serine protease inhibitors that modulates the activity of plasminogen activator and thrombin, is implicated in many biological processes. In the present study, we purified SERPINE2 from mouse seminal vesicle secretion (SVS), using liquid chromatography and identified it by liquid chromatography/tandem mass spectrometry, and it showed potent inhibitory activity against the urokinase-type plasminogen activator. SERPINE2 was expressed predominantly in seminal vesicles among murine male reproductive tissues. It was immunolocalized to the SVS and mucosal epithelium of the seminal vesicle, epididymis, coagulating gland, and vas deferens. In the testes, SERPINE2 was immunostained in spermatogonia, spermatocytes, spermatids, Leydig cells, and spermatozoa. SERPINE2 was also detected on the acrosomal cap of testicular and epididymal sperm and was suggested to be an intrinsic sperm surface protein. The purified SERPINE2 protein could bind to epididymal sperm. A prominent amount of SERPINE2 was detected on ejaculated and oviductal spermatozoa. Nevertheless, SERPINE2 was detected predominantly on uncapacitated sperm, indicating that SERPINE2 is lost before initiation of the capacitation process. Moreover, SERPINE2 could inhibit in vitro bovine serum albumin-induced sperm capacitation and prevent sperm binding to the egg, thus blocking fertilization. It acts through preventing cholesterol efflux, one of the initiation events of capacitation, from the sperm. These findings suggest that the SERPINE2 protein may play a role as a sperm decapacitation factor.
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PMID:SERPINE2, a serine protease inhibitor extensively expressed in adult male mouse reproductive tissues, may serve as a murine sperm decapacitation factor. 2108 13