Prostasome Membrane Associated Enzyme Activities and Semen Parameters in Men Attending an Infertility Clinic

Abstract

Seminal plasma from 22 men attending an infertility clinic was subjected to preparative ultracentrifu-gation for 2 h at 105,000 g. The pelleted material as well as the supernatant thus obtained were investigated with regard to prostasome membrane-linked enzyme activities in relation to other semen parameters. The mean activity of Zn²⁺-dependent adenosine triphosphatase in the sedimented prostasome fraction was 1.45 ± 1.02 µmol (range 0.29–4.79) orthophosphate released per milligram protein and 20 min, while the corresponding figures for the supernatant were 0.56 ± 0.30 (range 0.12–1.29). Hence, 72% of the specific activity was sedimented, and 28% remained in the supernatant. The same pattern was recognized with regard to the other two enzymes investigated, although they displayed individual characteristics with regard to distribution after ultracentrifugation. The pelleted prostasome-linked mean aminopeptidase activity was 0.39 U/mg protein (81.9%), with only 0.087 U (18.1%) remaining in the supernatant. The corresponding figures for Γ-glutamyltransferase were 7.89 (60.4%) and 5.17 (39.6%) µkat/g protein, respectively. The different enzyme activities in the prostasome fraction and supernatant, respectively, were interrelated to each other and correlated significantly with r values between 0.73 and 0.93 (p < 0.001). It was concluded that a minor fraction of prostasomes remained in the supernatant after ultracentrifugation. A relationship existed between prostasomes and semen volume revealing a rather consistent pattern in that small volumes favoured the presence of comparatively more prostasomes in the supernatant and less prostasomes in the pelleted fraction than large volumes. In addition, the sperm concentration seemed to be another determinant of the distribution of prostasomes in seminal plasma on subsequent ultracentrifugation.

Motility Stimulant Effects of Prostasome Inclusion in Swim-Up Medium on Cryopreserved Human Spermatozoa

“…The pellet suspensions were pooled (1-2 mL) and applied to a Sephadex G 200 column (75 mL) (Pharmacia AB, Uppsala, Sweden), which was equilibrated and eluted with the above-mentioned isotonic Tris-HC1 buffer at a flow rate of 6 mLh. Fractions of 1.5-2 mL were collected and assayed for aminopeptidase activity, which is a marker enzyme for prostasomes [13]. Fractions with high aminopeptidase activity were pooled and ultracentrifuged again for 2 h at 100,OOOg.…”

Prostasome Involvement in the Development and Growth of Prostate Cancer~!2009-07-10~!2009-12-09~!2010-02-11~!

“…They contain also γ-glutamyltransferase whose activity in seminal plasma is more than 1000-fold higher than in normal serum [72]. The prostate is the major source of this enzyme [73] and the most of it is bound to the membrane of the prostasomes [74].…”

Prostasome‐derived proteins capable of eliciting an immune response in prostate cancer patients

“…Fractions with elevated UV absorbance were collected and analyzed for aminopeptidase N activity, a marker enzyme for prostasomes. 17 Ultraviolet-absorbing fractions with high aminopeptidase N activity were pooled and ultra-centrifuged at 100,000 g for 2 hr. The pellet representing the ''purified prostasomes'' was resuspended in the isotonic Tris-HCl buffer and adjusted to a protein concentration of 2 mg/ml using a Protein Assay ESL method (Roche Diagnostics, Mannheim, Germany).…”