The soybean, sunflower and peanut seeds cotyledons accumulate and storage great
amount of protein and lipids. This reserve lipids, in seedlings germination, are transform glucose
molecules, by glyoxylate cycle. The acetyl CO-A formed by lipids is converted in malate, by
glyoxylate cycle, and the malate is used as na oxalacetate source to gluconeogenesis. Thus, the
plants can produce the liquid syntheses of glucose from the lipids. The principal enzymes are
isocitrate liase and malate synthase. The objective of this work was to determinated the activity of
the isocitrate lyase using exogenous isocitrate sodium substrate. Greater activity and specific activity
rates were observed using the exogenous substrate. It was also observed an activity at the second
and 8th germination day.