Distribution of marker enzymes from fractions derived from a nonaqueous density gradient of freeze-dried, sonicated celery leaves. Typically, distribution of α-mannosidase (EC 3.2.1.24) is in the vacuole, NADP-dependent reversible glyceraldehyde-3-P dehydrogenase (GAP-DH, EC 1.2.1.13) is in the chloroplast, and PEP carboxylase (PEPcase, EC 4.1.1.31) is in the cytosol. Recoveries of the marker enzymes were in the range of 93% to 106% based on total activities in the unfractionated materials.