Pyridine Nucleotide Requirements of Fatty Acid Synthetases

Abstract

Abstract The multienzyme fatty acid synthetase complexes from Mycobacterium phlei, Euglena gracilis, and Saccharomyces cerevisiae require both TPNH and DPNH for optimal efficiency. In the presence of both nucleotides, the Km values for TPNH and for DPNH for all three synthetase complexes are less than 5 µm. By measuring the formation of triacetic acid lactone in the presence of either DPNH or TPNH, it has been possible to show that in M. phlei TPNH is the specific coenzyme for the β-ketoacyl reductase step while DPNH is preferentially utilized in α,β-enoyl reduction.