Table I.

Activities of marker enzymes in cells and chloroplasts of wild-type and transgenic plants underexpressing (lines 801, 1002, and 1003) and overexpressing (lines 802, 202, and 1001) PMSR4

Line	Subcellular Fraction	G3PDHa	Percent Activity in Chloroplast	PEPCb	Percent Activity in Chloroplast
		μmol min−1 mg−1		μmol min−1 mg−1
Wild-type	Crude extract	1.47	255 ± 34	3.34	2.0 ± 1.9
	Chloroplast	2.23		0.07
801	Crude extract	1.63	185 ± 18	1.98	3.5 ± 2.8
	Chloroplast	2.72		0.07
1002	Crude extract	1.05	281 ± 1.9	1.72	3.3 ± 2.8
	Chloroplast	2.92		0.06
1003	Crude extract	1.80	264 ± 17	1.71	3.2 ± 2.2
	Chloroplast	3.21		0.08
802	Crude extract	1.77	264 ± 28	2.04	3.8 ± 2.6
	Chloroplast	3.29		0.08
202	Crude extract	1.70	201 ± 3	1.70	2.7 ± 1.4
	Chloroplast	3.47		0.07
1001	Crude extract	1.32	192 ± 50	1.32	3.6 ± 2.3
	Chloroplast	1.85				0.06

Data are presented as μmol min⁻¹ mg⁻¹ chlorophyll for a representative experiment. The percentage of activity in the chloroplast fraction corresponds to the mean ± sd for three independent chloroplast preparations of 32 plants grown under optimal growing conditions as described in “Materials and Methods.”

^aChloroplast marker, NADP-dependent G3PDH.

^bCytosolic marker, PEPC.