Subcellular localization of isocitrate lyase in nongreen tissue culture cells.

Density gradient centrifugation and electron microscopy were used to establish that isocitrate lyase present in Rosa cv. Paul's Scarlet cells was located in the mitochondria and not other membrane fractions. The enzyme may be important in glycine and serine synthesis. A comparison between the enzymic activity of isocitrate lyase and the amount of glycine and serine synthesized during logarithmic growth indicated that the activity was great enough to account for all of the carbon entering these amino acids during that stage of growth.