Cobalamin binding proteins in human seminal plasma.

Area of Science:

• Reproductive Biology
• Biochemistry
• Urology

Background:

• Seminal plasma contains significantly higher concentrations of transcobalamin (TC) and haptocorrin (HC) compared to blood.
• These vitamin B12-binding proteins play crucial roles in biological systems.

Purpose of the Study:

• To quantify seminal plasma TC and HC concentrations in normal individuals.
• To investigate the impact of vasectomy on seminal plasma TC levels.
• To compare the physicochemical properties of seminal plasma TC with that of blood TC.

Main Methods:

• Measurement of substance concentrations of TC and HC in seminal plasma and blood.
• Analysis of TC from seminal plasma and blood using Stokes radius and isoelectric point determination.

Main Results:

• Normal seminal plasma exhibited TC concentrations of 3.6-21.9 (median 8.4) nmol l-1 and HC concentrations of 1.4-8.6 (median 3.0) nmol l-1.
• Post-vasectomy seminal plasma showed significantly lower TC concentrations, ranging from 2.2-2.9 (median 5.3) nmol l-1.
• The Stokes radius and isoelectric points of seminal plasma TC were identical to those of blood TC.

Conclusions:

• Seminal plasma is a significant reservoir for TC and HC.
• Vasectomy leads to a notable reduction in seminal plasma TC concentrations.
• The molecular characteristics of TC in seminal plasma are consistent with those found in blood.