抄録
In the Fumoto's method, octopine is freed from arginine by the preliminary treatment with an Amberlite IRC-50 resin (pH 4.7) and photometrically determined by a modified method of Sakaguchi reaction. Applicability of this method was examined for the determination of octopine in squid muscle. As a result of the test using squid muscle extracts, recovery of added octopine was 90.9 ?? 97.9% (Table 1).
Subsequent experiments in which octopine and free arginine were determined from the muscle extracts of two species of squid, revealed the following points.
(1) A sample of Ommastrephes sloani pacificus STEENSTRUP contained free arginine smaller and octopine larger in amount than a ample of Sepioteuthis lessoniana FERUSSAC (Table 2).
(2) However, the total amount of the substances always constituted one third of the extractive nitrogen in the muscles, regardless of the different species.
(3) During the storage of Sepioteuthis lessoniana FERUSSAC at 5° ?? 7°C, free arginine rapidly decreased and octopine increased in the muscle (Fig. 1).
From these results, the species-difference observed in the amount of octopine or free arginine in squid muscle was supposed to be due to either one of the following; post mortem duration is different between materials used, or rate of conversion of free arginine to octopine varies between species of the squid.
