. 2002 Sep;130(1):244–255. doi: 10.1104/pp.003392

Table II.

Activities of GPC-PDE and different enzyme markers in carrot cells and in vacuoles

Enzymatic Activity	Crude Cell Extract	Vacuoles
GPC-PDE
Expressed per milligram of proteins (μmol h⁻¹ mg⁻¹)	0.24^a	2.2
Expressed per gram fresh wt (μmol h⁻¹ g⁻¹)	5.1	0.54
Recovery rate (%)	100	13
α-Mannosidase
Expressed per milligram of proteins (μmol h⁻¹ mg⁻¹)	0.51	4.86
Expressed per gram fresh wt (μmol h⁻¹ g⁻¹)	10.7	1.19
Recovery rate (%)	100	11
Glc-6-PDH
Expressed per milligram of proteins (μmol h⁻¹ mg⁻¹)	10.0	4.7
Expressed per gram fresh wt (μmol h⁻¹ g⁻¹)	210	1.15
Recovery rate (%)	100	0.54

Specific activities are expressed as micromoles of choline released per hour per milligram of protein or per gram fresh wt. α-Mannosidase was used as a vacuole marker; Glc-6-PDH was used as a cytoplasm marker. Recovery rate is defined as the ratio between cell and vacuole GPC-PDE activities expressed per gram fresh wt. As deduced from the α-mannosidase and Glc-6-PDH activities, vacuole contamination by cytosol did not exceed 5%.

Intracellular GPC-PDE activity from the crude cellular extract was estimated as the difference between the total GPC-PDE activity and the extracellular activity (see Fig. 6).