Abstract
Isocitrate lyase (EC 4.1.3.1) was purified from the peroxisome-containing particulate fraction of an alkane-grown yeast, Candida tropicalis, which had a conspicuous number of peroxisomes. The properties of the isocitrate lyase, which was induced by alkanes and localized in peroxisomes, were compared with those of the constitutive enzyme purified from glucose-grown cells of the yeast, which contained only a few pre-existing peroxisomes. The molecular masses of both enzymes were estimated to be about 130, 000 daltons by gel-filtration chromatography, and they were both composed of two identical subunits of a molecular mass of 65, 000 daltons. Both enzymes showed similar peptide maps upon partial digestion with proteolytic enzymes and were indistinguishable immunochemically, although there was a slight difference in their amino acid compositions.
