Antioxidant enzymes in the honey bee, Apis mellifera

Catalase (CAT), glutathione S-transferase (GST) and superoxide dismutase (SOD) activities were determined in postmitochondrial fractions of tissue homogenates (spermathecae, muscle and ventriculi), in hemolymph plasma, and in semen of honey bees. The highest CAT activity was found in semen (4.8 mU/mug fresh weight), and the enzyme was confined to the spermatozoa. CAT and GST activities of ventriculi exceeded those of other tissues and hemolymph, CAT being highest in mated queen ventriculi (2.7 mU/mug) and GST highest in worker ventriculi (10 mU/mug). Spermathecae of mated queens had higher CAT and GST activities (0.84 mU/mug, and 2.4 mU/mug, respectively) than virgin spermathecae (0.15 mU/mug, and 1.6 mU/mug). SOD activities (15-59 mU/mug) varied less than activities of CAT or GST between tissues. Seminal plasma contained two thirds of the total SOD activity of semen and one third was in the spermatozoa. The substantial activities of all three enzymes in spermathecae of mated queens suggest their involvement in the long-term protection of the spermatozoa from oxidative stress.