Über die Konzentration des Trypsin-Inhibitors im Sperma von Gesunden und andrologisch Kranken und über ihre Beziehung zu anderen Parametern des Spermas

Quantitative determination of high molecular weight serum proteinase inhibitors in human semen

Immunochemical determinations of serum proteinase inhibitors in human semen showed the presence of alpha1-antitrypsin and alpha1,x-antichymotrypsin, whereas inter-alpha-trypsin inhibitor, antithrombin III, alpha2-neuramino-glycoprotein and alpha2-macroglobulin could not be detected. Both serum proteinase inhibitors were determined in the seminal vesicle secretions of two patients with prostatic cancer. Employing the Ouchterlony double immunodiffusion technique pattern of identity was found between alpha1-antitrypsin resp. alpha1,x-antichymotrypsin in seminal plasma, seminal vesicle secretions and serum. Mean alpha1-antitrypsin concentration in seminal plasma of 129 andrological patients was 97.7 mug/ml and that of alpha1,x-antichymotrypsin 32.8 mug/ml. There were no differences in the mean alpha1-antitrypsin concentrations of normozoospermic and oligozoospermic ejaculates and those with seminal plasma fructose deficiency. Azoospermic ejaculates, however, showed a significant decrease of the mean alpha1-antitrypsin concentration (p less than 0.05). Alpha1,x-antichymotrypsin concentrations of normozoospermic ejaculates were significantly higher compared to those of oligozoospermia and azoospermia (p less than 0.05). Alpha1,x-antichymotrypsin levels in semen samples were fructose deficiency were not different from those of the total ejaculate population. The cause and significance of the observed differences in the inhibitor concentrations within the different ejaculate types is not known. However, there are no indications for the involvement of both proteinase inhibitors in male reproductive processes.

A new acrosin inhibitor from boar spermatozoa

A new proteinase inhibitor (Mr 7500) was isolated to apparent homogeneity from boar spermatozoa by repeated gel filtration on Sephadex G-50 and affinity chromatography on concanavalin-A--Sepharose 4B. The inhibitor strongly inhibits boar acrosin in a competitive 1:1 stoichiometric reaction with Kass = 7 x 10(10)1 mol-1. The inhibitor is a glycoprotein and represents a first member of a new class of proteinase inhibitor with a rather short polypeptide backbone of only 42 amino acid residues and a low cystine content. The basic protein (isoelectric point 9.4) contains a single disulfide loop, which is easily reducible by sodium borohydride. Upon reduction the inhibitory activity is lost, but rapidly regained after air reoxidation of the corresponding half-cystine residues. The reactive site residue was established to be arginine by inhibition with 2,3-butanedione. The inhibitor is rather specific for acrosin and inhibits bovine trypsin only to a limited extent. However, incubation with catalytic amounts of trypsin (or acrosin) at acid pH (pH2-3) rapidly leads to a limited proteolysis at the reactive site with formation of 67% modified (reactive site hydrolysed), but still active inhibitor. The equilibrium constant was established to be Khyd = 2.0.