Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new anionic acrosin inhibitor was found in an acidic extract of boar spermatozoa. The protein was purified by hydrophobic and ion exchange chromatography. According to gel filtration and SDS-electrophoresis the inhibitor preparation shows a molecular mass of Mr approximately 6000-7000 daltons. The isoelectric point is close to pH 4.5. It is an effective inhibitor of boar acrosin and bovine trypsin, but it does not inhibit porcine plasmin and pancreatic kallikrein or bovine chymotrypsin. An inhibitor with identical properties was found in high concentration (97% of the total acrosin inhibiting activity) in the fluid of cauda epididymis and also as a minor acrosin inhibiting component (2% of total acrosin inhibiting activity) in seminal plasma. The results indicate that binding of the inhibitor to spermatozoa may have taken place in the epididymis.
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PMID:Demonstration of an anionic acrosin inhibitor in spermatozoa epididymal fluid and seminal plasma of the boar. 390 26

A three-dimensional network of irregular anastomosing strands, referred to as "cords," was found to be the main component of the lamina densa of a) common, "thin" basement membranes in tissues from diverse origins including foot pad epidermis, trachea, jejunum, seminiferous tubule and vas deferens of the rat, monkey seminiferous tubule, and mouse ciliary process, b) a "double" basement membrane, the rat glomerular basement membrane, and c) "thick" basement membranes including rat Reichert's membrane, mouse lens capsule and the Engelbreth-Holm-Swarm (EHS) tumor matrix. The average thickness of the cords was 3.2-4.8 nm, 4 nm, and 4.7-5 nm, respectively, in these three types of basement membranes. The mean diameter of the intercordal spaces, or openings of the network, averaged 14 nm with a range from 8 nm in the glomerular basement membrane to 21.9 nm in the lens capsule. After cryofixation followed by freeze substitution or freeze drying, similar cord networks were observed in all basement membranes examined which included two thin basement membranes, that of the rat epididymis and seminiferous tubules, and three thick basement membranes, that is, the lens capsule and the EHS tumor matrix of the mouse, and rat Reichert's membrane. In addition, following the co-incubation of laminin, type IV collagen and heparan sulfate proteoglycan at 35 degrees C, a precipitate was formed which was found to contain lamina densa-like sheets and large semisolid masses. Both types of structures were found to be made up of a network of 3 nm wide cords, which resembled that of natural basement membranes. With the immunoperoxidase technique, these cords were stained for major basement membrane components including laminin, type IV collagen, heparan sulfate proteoglycan, entactin, and fibronectin. Ribbon-like "double tracks" 4.5 nm in width and being distributed along cords have been identified as the form taken by heparan sulfate proteoglycan in basement membranes. Following mild plasmin treatment, most of the cord components were digested away leaving behind a network of fine filaments found to contain type IV collagen. Each cord, therefore, is organized by a type IV collagen core filament which is surrounded by a plasmin-sensitive sheath containing other basement membrane components. Two types of minor structural components, that is, 7-10 nm wide straight "basotubules" and 3.5 nm wide particulate structures referred to as "pentosomes" were associated with cord network in some basement membranes.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Basic structure of basement membranes is a fine network of "cords," irregular anastomosing strands. 806 56