Abstract
Comparative studies on the activities of isocitrate lyase and malate synthase were performed in the cells of Candida yeasts grown on media containing glucose, n-alkane or acetate as the sole carbon source. In general, the activities of both enzymes were higher in the cells growing on n-alkane or acetate than in those growing on glucose. When the yeasts were cultivated on glucose, the level of the isocitrate lyase activity in C. tropicalis was enhanced after the middle phase of growth, while the activity in C. lipolytica was maintained at a low level. The synthesis of isocitrate lyase in C. tropicalis growing on n-alkane or acetate was repressed by the addition of glucose to the medium, and derepressed when the cells grown on glucose were transferred to n-alkane or acetate media, indicating that glyoxylate cycle has an important role in the metabolism of n-alkane as well as acetate. Cycloheximide inhibited the synthesis of isocitrate lyase in C. tropicalis growing on n-alkane or on acetate.
