Isolation and characterization of organelles from soybean suspension cultures

Whole homogenates from cells of Glycine max grown in suspension culture were centrifuged on linear sucrose gradients. Assays for marker enzymes showed that distinct peaks enriched in particular organelles were separated as follows: endoplasmic reticulum (density 1.10 g/cm(3), NADH-cytochrome-c reductase), Golgi membranes (density 1.12 g/cm(3), inosine diphosphatase), mitochondria (density 1.18-1.19 g/cm(3), fumarase, cytochrome oxidase) and microbodies (density 1.21-1.23 g/cm(3), catalase). In cells which had ceased to grow (stationary phase) only a single symmetrical catalase peak at density 1.23 g/cm(3) was observed on the sucrose gradient. During the phase of cell division and expansion a minor particulate catalase component of lighter density was present; its possible significance is discussed.