CH2-C0O- CH2-C0O- 0=0 =0 CH2 =0 CH2-C00- =0 CH2 4H* + 4 b2 CH2 CH2-C00 0=0 CH2 4H* Fatty acid C02 synthase C02 C02 four more additions 软脂酸的生物合成 HS FIGURE 21-3 The overall process of palmitate synthesis.The fatty acyl chain grows by two-carbon units donated by activated malonate,with loss of CO at each step. HS The initial acetyl group is shaded yellow,C-1 and C-2 of malonate are shaded pink, and the carbon released as CO2 is shaded green.After each two-carbon addition, 0 reductions convert the growing chain to a saturated fatty acid of four,then six,then eight carbons,and so on.The final product is palmitate (16:0). Palmitate 软脂酸的生物合成