Figure 6.

Activation of purified recombinant biotin synthase by plant organelle extracts (plant-reconstituted system). A, Biotin synthase activity was measured under optimized conditions with 0.5 nmol purified Bio2 protein from Arabidopsis alone (none), or in the presence of 0.5 mg of protein extracts from isolated pea (Pisum sativum) leaf organelle (chloroplasts and mitochondria) subfractions, added separately or in combination, as indicated on the figure. B, Biotin synthase activity was measured under optimized conditions with 0.5 nmol purified Bio2 protein from Arabidopsis, in the presence of 0.5 mg of protein extracts from isolated potato (Solanum tuberosum) tuber mitochondria subfractions, added separately or in combination, as indicated in the figure. Biotin produced was determined by a turbidimetric microbiological method using L. plantarum. The error bars represent sds from three independent measurements, and when not shown fall within the column. St, Stroma; Mb, membranes; Ma, matrix).