Table 1.
Analysis of Marker Enzymes in Membrane Fractions Isolated by Aqueous Two-Phase Partioning Procedure with the Total Protein and Marker Enzyme Activities in the Microsomal, Plasma Membrane, and Intracellular Membrane Fractions
| Fraction | Protein mg (%) | Plasma membrane ATPase nmol s−1 (%) | Mitochondria membrane Cyt c oxid. nmol s−1 (%) | ER membrane Cyt c red. nmol s−1 (%) |
|---|---|---|---|---|
| MF | 60 | 380 | 21 | 200 |
| U3 | 5.7 (9.5) | 357 (94) | 0.42 (2) | 62 (31) |
| L1 | 36.6 (61) | 15.2 (4) | 13.4 (62) | 108 (54) |
ATPase activity for plasma membrane was determined in the presence of 0.025% (v/v) Triton X-100 and 50 μM vanadate. The enzymes assayed for the mitochondria and ER were NADPH–cytochrome c oxidase and NADPH–cytochrome c reductase, respectively. Cyt c oxid., NADPH–cytochrome c oxidase; cyt c red., NADPH–cytochrome c reductase; L1, intracellular membrane fractions; MF, microsomal fractions; U3, plasma membrane fractions.