Artifacts in Intracellular Enzyme Distribution Caused by Alkaline Homogenates

Many papers report the simultanieous occurrence of the same enzymes in several subcellular fractions from planits. Isocitrate dehvdrogenase was observed in the mitochondrial and the soluble fraction from lettuce !(7) and peas (3), and these 2 fractions from apples both contained malic enzyme (5). Glucose6-P dehydrogenase was recorded in these 2 fractions from lettuce (6), carrot )(4) and pea (9). Mitochondrial and soluble P-enolpyruvate (PEP) -carboxylase and PEP-carboxvkinase were reported for castor beans (1), and PEP-carboxvlase was recorded in chloroplasts as well as the soluble fraction from cactus (8). In these investigations a great variation in the preparation of homogenates, the starting point for cell fractionationi, can be observed: molarity (0.0250.2 ai). p)H (7.4-7.9), and the kind of buffer (tris