Identification of a female-specific hemocyanin in the mud crab, Scylla olivacea (Crustacea: Portunidae)

Copper-containing proteins, hemocyanins, are respiratory proteins of crustacean decapods. In this paper, 14 a novel female-specific hemocyanin (FSH) in the mud crab, Scylla olivacea (Crustacea: Portunidae), is reported. FSH occurs in the hemolymph of adult females with maturing ovaries, but not in the hemolymph of juveniles of either sex or in adult males. FSH was purified from the hemolymph of females with maturing ovaries by liquid chromatography. Further analysis revealed that FSH is a carbohydrate-rich protein; no cross-immune reaction was found between FSH and vitellin; furthermore, it does not resemble vitelloprotein molecules. It has characteristics in common with other better-known hemocyanins, such as its copper content and oxygen-binding ability. The P-50 of FSH is 28.3 mmHg O2, and its oxygen saturation point is 152 mmHg. From evidence of its oxygen-binding ability, it is certain that FSH is a unique hemocyanin of female crabs with maturing ovaries, and its functions are supposedly correlated with reproduction in female crabs.