Table II.

ATP sulfurylase and APS reductase activity in chloroplasts free of mitochondrial contamination

Chloroplast Sample	Specific Enzyme Activity
	NADP-GAPDH	Cyt c oxidase	ATP sulfurylase	APS reductase
	nmole · min−1 · mg protein−1
Crude chloroplasts	498	28	33	2.1
Percoll-purified chloroplasts	812	0	32	1.8

Chloroplasts isolated from 47-d-old plants were prepared by low-speed centrifugation of lysed protoplasts (crude chloroplasts) or were subjected to further purification by Percoll density gradient centrifugation. The values for crude chloroplasts represent the mean of three independent measurements and the Percoll-purified chloroplasts of two independent measurements. The marker enzymes are as described in Table I.