Table 1. CA/CB molar ratio in three different lots [A: white variety from Queluzito; B: yellow variety from Carrancas; C: reference venom from FUNED used in anti-crotalic serum production (white)] of Crotalus durissus terrificus crude venom and in their respectively purified CTX.

Venom identification	Concentration (μM)
	CA		CB		Molar ratio CB/CA
	Venom	CTX	Venom	CTX	Venom	CTX
A	9.95	12.00	10.91	11.35	1.10	1.04
B	89.86	15.17	77.86	15.73	0.87	1.04
C	22.10	29.53	20.17	28.48	0.91	0.96
Mean					0.96	1.01

The molar ratio was calculated by 280 nm absorbance under curve integration after reversed phase chromatography. Based on the average amino acid compositions of the CA and CB isoforms, molar extinction coefficients at 280 nm (12,761 cm⁻¹M⁻¹ and 32,190 cm⁻¹M⁻¹, respectively) were used in the calculations.