The Estimation of the Quantity of Isocitrate Lyase Protein in Acetate-Adapted Cells ofChlorella pyrenoidosa

Abstract

The quantity of isocitrate lyase protein was estimated, as a percentage of cell dry weight, by three different electrophoretic methods: (a) direct collection and determination of proteins after electrophoresis; (b) separation and estimation of ₃₅S-labelled proteins; (c) estimation from the density of stained bands on acrylamide gels. The possibility that protein-protein interaction during electrophoresis might interfere with the results was considered and discounted. The average result from the three methods is that, in acetate-adapted cells of Chlorella pyrenoidosa, isocitrate lyase protein constitutes about 7.0 per cent of total soluble proteins (100,000 g supernatant), that is 1.0 per cent of cell dry weight. The estimate agrees well with one based on the increase in specific activity of the enzyme during purification.