EFFECT OF GERMINATION ON THE PROTEIN-CONTENT AND ON THE LEVEL OF SPECIFIC ACTIVITY OF LIPOXYGENASE-1 IN SEEDLINGS OF 3 SOYBEAN CULTIVARS

The effect of germination on the protein content and in the level of s pecific activity of lipoxygenase-l on seedlings of Santa Rosa, FT-2 an d Davis soybean cultivars were studied. Soybean seeds of the three cul tivars were germinated from 0 to 72 hours in a seed germinator at 30 d egrees C temperature, 100% relative humidity, and absence of light. Th e seeds were then frozen in liquid nitrogen, freeze-dryed and milled. The lipoxygenase-l was extracted with 0,02M thris-HCl buffer at pH=8,2 and 13% saccharose for 30 minutes at 4 degrees C without shaking. The highest levels of specific activity of lipoxygenase-1 per miligram of flour (dry basis) in the Santa Rosa, FT-2 and Davis cultivars were ob served between 18 and 36, 18 and 24, and 0 and 12 hours, respectively. The polinomial quadratic model best fits the regression analysis of t he variable levels of specific lipoxygenase activity for cultivar Davi s (R(2)=0,9197). Although for cultivars Santa Rosa (R(2)=0,9041)., and FT-2 (R(2)=0,7486) the 4th degree polinomial model has shown the best fit. The protein content in the three cultivars studied reached the m aximum values at 48h germination. The germination induced a relative i ncrease of the protein content but caused a reduction of the level of specific lipoxigenase-1 activity.