Table 1.

ID requirement for fatty acid synthesizing center generated by reconstitution of various recombinant domains

TRX-hFAS fusions	Partial activities, nmol/min per mg						Fatty acids, cpm
	AT	MT	DH	KR	ER	TE
DI-ID-N	752	594	119				685
ID-C-DII-III				1,158	43	98	90
DI	475	257	ND				32
DII-III				630	68	80	72
DI-ID-N + ID-C-DII-III							24,750*
DI-ID-N + DII-III							240
DI + ID-C-DII-dIII							46
DI + DII-III							31

The construction of TRX-hFAS fusion plasmids is described in Materials and Methods and in Fig. 2. The expression of recombinant proteins in E. coli, purified by using TALON resin, and the determination of partial activities, were performed as described (23, 24). The reconstitution of FAS activities from the various recombinant halves of the human FAS subunits and the determination of fatty acid synthesis were carried out by using [2-¹⁴C] malonyl-CoA, acetyl-CoA, and NADPH as substrates (24). AT, acetyl transacylase; MT, malonyl transacylase; DH, β-hydroxyacyl dehydratase; KR, β-ketoacyl reductase; ER, enoyl reductase; ND, not determined. 

^*These counts represent 9.8 nmol of fatty acids synthesized.