Identification and characterization of fructose-1, 6-diphosphate aldolase in seminal fluid of the silkworm, Bombyx mori

抄録

 Fructose 1, 6-bisphosphate aldolase (EC 4.1. 2.13.; ALD) is an enzyme that is central to glycolysis and gluconeogenesis in the cytoplasm of higher organisms. In the silkworm, Bombyx mori, this enzyme exists primarily in the form of tissue-specific homotetramers BmALD2 (type-S) or BmALD1 (type-F), mainly in the fat body and muscle, respectively. In the present study, a consistently high level of ALD activity was detected in the glandula (g.) lacteola, one of the exocrine glands of the male reproductive system, which was transmitted without loss upon mating to the spermatophore formed inside of the female bursa copulatrix . The overall kinetic properties of this seminal ALD are similar to those of the previously studied type-F. In addition, reverse transcription-polymerase chain reaction analysis showed that BmALD1 was predominantly expressed in the g. lacteola. These data strongly suggest that the seminal fluid contains type-F ALD, which is a homotetramer of BmALD1, which has higher overall enzymatic activity, achieves greater rates of extracellular glycolytic output, and can support sperm maturation in the spermatophore.