Proteins in spermathecal gland secretion and spermathecal fluid and the properties of a 29 kDa protein in queens of Apis mellifera

One and two dimensional SDS-PAGE were used to characterize the protein pattern of the spermathecal gland secretion and spermathecal fluid in Apis mellifera queen pupae and emerged queens of different ages. The concentration of protein varied from 8.5 and 15.3 mg/mL in the spermathecal fluid, and from 5 to 8.5 mg/mL in the secretion. Development of the protein pattern of the gland secretion and spermathecal fluid was identical from pupae until the age of 3 days. In sexually mature queens (10 days or older) the gland secretion and spermathecal fluid each had one additional band at 79 kDa and at 29 kDa respectively. The 29 kDa protein was N-terminal blocked but several peptide fragments were sequenced after digestion with LysC protease. Only 2 of the sequences showed a distinct homology to the N-terminal half of the glycolytic enzyme triosephosphate isomerase (TPI). TPI antibody reacted with the 29 kDa protein, but the enzymatic activity was only 1/100 compared to TPI of hemolymph. The possible function of the protein is discussed.