Platymiscium pubescens seeds were placed to soak in water and sampled for biochemistry and kinetic characterizations of embryonic axis and the alfa-galactosidase cotyledon enzyme. The specific activity in the embryonic axis increased from zero to 96 hours of imbibition, stabilizing soon after. The activity of the cotyledon enzyme showed a small increase in the same period. The alfa-galactosidase of the embryonic axis presented its maximum activity in the interval of pH 4.5 to 6.0. On the other hand, for the cotyledon enzyme, the highest activity was detected in the interval of 4.0 to 6.0. The temperature of 55ºC was best to stimulate embryonic axis and cotyledon alfa-galactosidase acticvity. Enzymes of the embryonic axis and the cotyledons were heat tolerant, not reaching the half life at 40ºC, in 1.500 minutes. The embryonic axis alfa-galactosidase activity was inhibited by melibiose, CuSO4 and SDS, while that of cotyledons was for all the effectors, except for SDS, CuSO4 and galactose which had neutral effect. The values of K M for the embryo and for the cotyledon alfa-galactosidases were 3.37 and 0.26 mM, respectively.
forest specie; alfa-galactosidase; enzyme
