Abstract
Stability of Ficin A, B, C and D from Ficus carica var. HORAISHI was examined with measurement of proteinase activity and ultraviolet difference spectra. The inactivation and disruption of hydrophobic part of the enzymes by guanidine hydrochloride decreased in the order of Ficin D>B>A>C. These enzymes were completely inactivated at the concentration of guanidine hydrochloride where the enzymes showed maximum blue shift. In the presence of ethylene glycol, the order of inactivation and disruption of hydrophobic part of the enzymes was Ficin A=B=D>C, and inactivation and disruption of hydrophobic part of Ficin D were stronger than those of Ficin B by urea, while Ficin A and C were stable in 10M urea. In the presense of dimethyl sulfoxide, the stability of the enzymes and the value of refractive index of hydrophobia part of the enzymes decreased in the order of Ficin C>A>B>D. Spectrophotometric titration of the enzymes indicated that the order of dissociation of tyrosine residues was Ficin D>B>A>C. From these results, it is suggested that the stability of Ficin A, B, C and D depends on the hydrophobic part of the enzymes and that the refractive index of hydrophobic part of these enzymes indicates the stability of Ficin A, B, C and D.
