Intracellular localization of enzymes in leaves and chloroplast membrane permeability to compounds involved in amino acid syntheses.

1. Enzyme distribution between chloroplasts and the nonchloroplast parts of green leaf cells of Spinacia oleracea, Nicotiana rustica, Vicia faba, and Phaseolus vulgaris have been investigated by use of the nonaqueous chloroplast isolation technique. Whereas pyruvate kinase and peroxidase were located only or mainly outside of the chloroplasts, the other enzymes studied, isocitric dehydro­ genase, glutathione reductase, NADand NADP-dependent pyridine nucleotide quinone reductase, malic dehydrogenase, NADand NADP-dependent glyoxylate reductase, glutamate-oxaloacetate transaminase, NAD-dependent glutamic dehydrogenase, and NADP-dependent aspartic dehydro­ genase were both inside and outside of the plastids. In contrast, NADP-dependent glyceraldehyde3-phosphate dehydrogenase is located only within the chloroplasts. 2. Intact isolated spinach chloroplasts incorporated only a very small amount of labeled carbon