March 2013 (No. 1)
Superoxide dismutase (SOD) in boar spermatozoa: Puriﬁcation, biochemical properties and changes in activity during semen storage (16°C) in different extenders
Aleksandra Orzołek, Paweł Wysocki *, Jerzy Strzeżek, Władysław Kordan
Department of Animal Biochemistry and Biotechnology, University of Warmia and Mazury, Olsztyn, Poland
The antioxidant system in semen is composed of enzymes, low-molecular weight antioxidants and seminal plasma proteins. Loss of enzymatic activity of superoxide dismutase (SOD) during semen preservation may cause insufﬁcient antioxidant defense of boar spermatozoa. The aim of this study was to isolate and characterize SOD molecular forms from spermatozoa and to describe changes in SOD activity in boar sperm during preservation at 16°C. Sperm extracts were prepared from fresh or diluted semen and used for SOD puriﬁcation or activity measurement. Ion-exchange chromatography and gel ﬁltration was used to purify SOD molecular forms. BTS, Dilu Cell, M III and Vitasem were used as diluents for 5-day storage of semen at +16°C. The molecular form of SOD released from spermatozoa after cold shock and homogenization had a molecular weight of approximately 67 kDa. The activity of the SOD form was the highest at pH 10 within the temperature range between 20 and 45°C. The enzymatic activity of form released after cold shock was inhibited by H2O2 and diethyldithiocarbamate (DDC; by 65 and 40%, respectively). The SOD form released by homogenization was inhibited by H2O2 and DDC (40%). The molecular form released after urea treatment was a 30 kDa protein with maximum activity at 20°C and pH 10. Enzymatic activity of this form was inhibited by H2O2 by 35%, DDC by 80% and 2-mercaptoethanol by15%. The antigenic determinants of SOD isolated from boar seminal plasma and spermatozoa were similar to each other. Susceptibility of spermatozoa to cold shock increased during storage, but the differences between extenders were statistically non-signiﬁcant.
Reproductive Biology 2013 13 1: 34–40.
* Corresponding author: University of Warmia and Mazury in Olsztyn, Department of Animal Biochemistry and Biotechnology, Oczapowskiego 5, 10-718 Olsztyn, Poland; E-mail address: firstname.lastname@example.org