THE ABSENCE OF GLYOXYLATE CYCLE ENZYMES IN RODENT AND EMBRYONIC CHICKLIVER

There have been several reports over the past decade of the presence o f the glyoxylate cycle enzymes, isocitrate lyase and malate synthase, in animal tissues. Reaction products in these assays have been measure d principally by chromatographic separation of isotopes or by colorime tric procedures. In this report more sensitive and accurate HPLC and H PCE analyses were used to detect enzymatic activity. Reversed phase HP LC revealed the absence of detectable isocitrate lyase activity in gui nea pig, Tat and chick embryonic liver. The formation of several other alpha-keto acids was detected and this may account for the previously reported activities. Using HPCE to monitor malate formation malate sy nthase activity was not detected in these tissues. These results indic ate that when assaying enzyme activities in crude tissue homogenates s pecific methods for the identification of end products are required.