The green rod pigment of the bullfrog, Rana catesbeiana.

The blue-sensitive pigment of the green rods was purified by column chromatography with Con A-Sepharose 4B. In digitonin solution, the lambda max and the epsilon max values of the green rod pigment were 430 nm and 35,000, respectively, for the vitamin A1-based pigment (P-4301). P-4301 was destroyed by hydroxylamine and p-chloromercuribenzoate but not by sodium borohydride. The regeneration rate of P-4301 was about 100 times faster than that of rhodopsin and the optimum pH for regeneration was at 6.5. P-4301 has properties intermediate between rhodopsin and the chicken cone pigment, iodopsin . The green rod pigment based on vitamin A2 was segregated in the dorsal retina. The lambda max and the epsilon max were 442 nm and 32,000, respectively. The amount of this pigment (P-4422) varied with season as did that of porphyropsin . P-4422 increased in November and reached a maximum of 33% of the total green rod pigment in the dorsal retina in March. The green rod pigment in the ventral retina was always based on vitamin A1 in all seasons. Regenerations of vitamin A2-based pigments of both green and red rods were slower than those of the respective vitamin A1-based pigments.