Figure 2.

Comparison of the acyl-CoA preference of the DGAT in WT and AS11 developing seed (mid-green stage). Seeds of WT and AS11 Arabidopsis were harvested, and homogenates were prepared and DGAT activity measured as described by Katavic et al. (1995). In the comparative specificity studies, the DGAT activity was assayed in the presence of 18 μm [1-¹⁴C]-labeled 18:1-CoA, 18:2-CoA, or 20:1-CoA, supplied individually, and 200 μm unlabeled sn-1,2-diolein. In the comparative selectivity study equal concentrations (18 μm) of [1-¹⁴C]-labeled 18:2-CoA and 20:1-CoA were supplied simultaneously to the seed homogenates in the presence of 200 μm unlabeled sn-1,2-diolein. Separation and measurement of the relative proportions of the radiolabeled TAG products (18:1/18:1/¹⁴C-18:1; 18:1/18:1/¹⁴C-18:2 or 18:1/18:1/¹⁴C-20:1) was conducted by reverse-phase radio-HPLC as described by Weselake et al. (1991).