Acid-extracted glycoproteins in human seminal coagulum

First report on purification of the predominant acidic coagulum protein of human semen prior to liquefaction

The predominant acidic coagulum protein of freshly ejaculated human semen under reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was purified for the first time from washed seminal coagulum keeping urea throughout the entire procedure. Washed seminal coagulum was isolated from fresh semen sample in acetate buffer at pH 4.5 at 0 degrees C, solubilized rapidly in deionized 4 M urea followed by reduction and carboxymethylation of disulfide bonds. By CM-Sephadex and Sephacryl S-300 high-resolution chromatography in presence of urea at room temperature, the predominant acidic coagulum protein was highly purified (99.1%) with a yield of 2.7% of the coagulum protein. The molecular weight of the purified protein in reducing SDS-PAGE was 162 kD.

Collective isolation of two major, close molecular weight coagulum proteins occurring in human semen before liquefaction

Two major, close molecular weight basic coagulum proteins of freshly ejaculated human semen identifiable on reducing SDS-PAGE, have been isolated together from washed seminal coagulum. The latter was solubilized in urea, followed by reduction and carboxymethylation of disulphide bonds. By high-resolution chromatography on carboxymethy-Sephadex and Sephacryl S-300 using 8 M urea in 0.1M Tris-HCl (pH 7.4) as eluate these proteins were isolated together (purity 99%) with a yield of 10.5%. The molecular weights of the isolated proteins on SDS-PAGE were 75 and 79 kD.

Deficiency in major high molecular-weight seminal proteins in men producing poorly coagulating and alkaline liquid ejaculates

Using SDS-PAGE three major high molecular-weight coagulum proteins (57, 75 and 79 kD) were identified in unliquefied human ejaculates. Washed coagulum was prepared at pH 4.5 and demonstrated negligible proteolysis as determined by a highly sensitive fluorescamine-based method. Laser densitometric scanning of these high molecular-weight proteins in unliquefied ejaculates in relation to their coagulational failure revealed that the total content of 57, 75 and 79 kD proteins in whole semen represented approximately 44% of levels in the normally coagulated, approximately 24% in poorly coagulated (P less than 0.005) and approximately 3% in the non-coagulated (alkaline liquid, P less than 0.001) samples. The findings imply that these predominant high molecular-weight proteins play a major role in human seminal coagulum formation.

Determination of total protein in human seminal plasma

Methodological problems are encountered in determinating human seminal protein content since results are influenced especially by techniques which are used, and by modifications due to liquefaction process. In order to test these two points, three methods (Folin, Biuret and Meulemans's reactions) were applied to the same seminal samples and results were compared. The differences seem principally due to the high level of glycoproteins. To determine the modifications of total protein content with time after semen collection, each sample was separated in aliquot fractions and proteolysis was blocked at different times for each fraction. There is an increase of the protein concentration during the first fifteen minutes that follows semen collection. The cause of this phenomenon is discussed.

Human seminal antiliquefying agents--a potential approach towards vaginal contraception

One-hundred-one natural and synthetic enzyme inhibitors or inactivators were screened in vitro against the liquefaction property of human ejaculates with a view to develop antiliquefying agents for vaginal contraception. Of those compounds, 27 demonstrated no effect, 36 quickened and 20 delayed the process of liquefaction, while 18 agents stopped it completely. The highly effective antiliquefying agents also showed spermicidal property and were found to coagulate even the liquid ejaculates. Compounds having antiliquefying property, together with coagulating and spermicidal activities, will offer a highly promising approach towards vaginal contraception.

Physical properties and non-enzymic components of human ejaculates. Relationship to spontaneous liquefaction

The relationship between spontaneous liquefaction and the characteristics of ejaculated human semen has been investigated. The liquefaction time of ejaculates was found to be significantly correlated with their extent of coagulation and some non-enzymic components of seminal plasma. Human ejaculates were classified into 3 distinct groups depending on their liquefaction time, and the groups were characterized physico-chemically. The liquefaction time also revealed a low but significant negative correlation with semen volume. It is concluded that an individual's ejaculatory characteristics can be evaluated simply by determining its liquefaction time.