Table I.

Enrichment of marker enzymes in endomembrane-enriched membrane fractions isolated from root tips of wheat cv PT741

Marker Enzyme	Cellular Location	Enrichment in Endomembrane Fractiona
		Mean	se
Bafilomycin A1-sensitive  ATPase	Tonoplast	1.43	0.24
Nitrate-sensitive ATPase	Tonoplast	3.35	1.15
Vanadate-sensitive  ATPase	Plasma membrane	0.45	0.19
Glucan synthase II	Plasma membrane	0.69	0.21
Cytochrome c oxidase	Mitochondria	0.35	0.02

Endomembrane-enriched membranes were isolated from microsomal membranes using a two-step gradient of Dextran T70 (2% and 10%), from which the interface was collected. Data are representative of three independent membrane preparations. Values shown are means ± se.

^a Enrichment in endomembrane fraction is calculated as endomembrane specific activity/microsomal specific activity.