Utilization of an improved methodology to isolate Lupinus albus conglutins in the study of their sedimentation coefficients.

摘要

Methods utilized frequently for the extraction of globulins from legume seeds lead to a considerable loss of these proteins in the albumin fraction due to a partial solubilization of globulins in the albumin extraction medium. The standard procedureto isolate legume seed globulins was modified by (i) including calcium and magnesium in the albumin extraction solution, which completely solubilizes the albumins free of contaminating globulins, and (ii) adding EDTA and EGTA to the globulin extractionsolution, which efficiently extract the globulins. Using this modified methodology, Lupinus albus globulins were isolated and subsequently purified, and the main individual globulins, namely alpha-, beta-, and gamma-conglutins, were characterized. Usingthe total globulin fraction or the purified conglutins on isopycnic sucrose or glycerol density gradient centrifugation performed under low or high ionic strength and on gel filtration techniques, it is proposed that beta-conglutin (with a sedimentationcoefficient of approximately 11 S) is considerably heavier than alpha-conglutin (with a sedimentation coefficient of approximately 7 S).