Chromatophorotropic neurohormones of the shrimp Crangon crangon. Partial purification of the red-pigment-concentrating hormone

Abstract

Three chromatophorotropic neurohormones, present in the aqueous extract of acetone-dried and powdered eyestalk of the shrimp Crangon crangon (L.), were separated by gel filtration on a Sephadex G-25 column in 0.1 M acetic acid containing 1 mM mercaptoethanol (Fig. 1). Gel filtration was performed in a cold room at 4°C. The red-pigment-concentrating hormone, after gel filtration on Sephadex G-25 column, was pooled and freeze-dried. The increase in total activity of red-pigment-concentrating hormone after gel filtration through Sephadex G-25 as compared with the total activity of this hormone in aqueous extract (Table 1) was caused by removal of black-pigment-dispersing hormone. Purification of red-pigment-concentrating hormone was achieved by repeated gel filtration on a Sephadex G-15 column. Red-pigment-concentrating hormone appeared as a symmetrical peak (the fourth peak in Fig. 3) when the absorbance of effluent was measured at 235 nm. Red-pigment-concentrating-hormone purified on Sephadex G-15 column has a specific activity about 9000 times greater than in the initial material.