LIPOXYGENASE-1 FROM SOYBEAN SEED INHIBITING THE ACTIVITY OF PANCREATIC LIPASE

There are some similar characteristics in protein nature between the l ipase inhibitor from soybean seed and soybean lipoxygenase-1 (LOX-1). Thus, the inhibiting protein for pancreatic lipase was prepared from d efatted soybean meal by the procedure for the isolation of LOX-1 [Axel rod et al., Methods in Enzymology, 71., 441-451 (1981)]. The LOX-1 fro m soybean seed dose-dependently inhibited the release of fatty acid fr om a soybean oil emulsion, and the concentration of LOX-1 to cause hal f inhibition of the lipase activity was 3.2 x 10(-7) M. The LOX-1 obta ined from E. coli transfected with a plasmid carrying the soybean LOX- 1 gene also inhibited the lipase activity. However, the lipase-inhibit ing activity by the LOX-1 was not affected by the presence of nordihyd roguaiaretic acid, an inhibitor for LOX, in the reaction mixture. Thes e results show that the soybean LOX-1 inhibits lipase activity regardl ess of its lipoxygenase activity.