Factors involved in synthesis of fatty acids from acetate by a soluble fraction obtained from lactating rat mammary gland

Fatty Acid Synthesis From Acetate by Human Liver Homogenate Fractions*

“…The complete extraction of the C"-fatty acids from these mixtures has been demonstrated in a previous report from this laboratory (29). Assay for nonsaponifiable C".…”

“…As already pointed out, TPNH is required for fatty acid synthesis (1,10,14,29). Although citrate oxidation produces TPNH, its production cannot be the sole factor involved in the citrate effect inasmuch as another TPNH-generating substrate, glucose-6-phosphate, could not be substituted for citrate.…”

“…For every 2-carbon elongation of the chain, 2 moles of hydrogen are needed. Experiments with pyridine nucleotides indicate that TPNH and, to a lesser extent, DPNH can serve as effective hydrogen donors for these reductive steps (29,48). A summary of these reactions is presented in the last line of Figure 3.…”

“…The C"'-fatty acids produced in the homogenate experiments were isolated and assayed as previously described (29). The complete extraction of the C"-fatty acids from these mixtures has been demonstrated in a previous report from this laboratory (29).…”

“…Cholesterol from the slice experiments was isolated as the digitonide (30) without the addition of carrier, dissolved in methanol, and assayed for C" as described above. The isolation of the nonsaponifiable fraction from hexane extracts in the homogenate experiments and the assay of its C" activity have been described (29).…”