Elongation of Acyl Carrier Protein Derivatives by Bacterial and Plant Extracts

Acyl derivatives of acyl carrier protein (ACP), chemically prepared from fatty acids of intermediate chain length and Escherichia coli ACP, are elongated by the fatty acid synthetase system of E. coli, by extracts of photoauxotrophic Euglena gracilis, and by spinach chloroplasts. These conversions require the presence of malonyl coenzyme A and of a reduced triphosphopyridine nucleotide-generating system. The E. coli system elongates octanoyl-ACP both to saturated and to unsaturated acids, but converts decanoyl-ACP and lauryl-ACP to saturated acids only. Extracts of Euglena convert the acyl-ACP derivatives of C8, C10, C12, and C16 fatty acids to stearate, oleate, and arachidate. The formation of oleic acid from these precursors requires aerobic conditions.