Distribution of yeast fatty acid synthetase subunits: three-dimensional model of the enzyme.

Rabbit and goat antibodies against the isolated alpha and beta subunits of yeast fatty acid aynthetase were raised and characterized. The purified IgG fractions were studied as to their capability to precipitate their antigens and the holoenzyme and to inhibit the partial reactions involved in overall fatty acyl-CoA synthesis. The specificity of the antibodies was investigated by immunodiffusion and by immunotitration. Native enzyme was crosslinked with each of the antibodies, and dimeric and oligomeric groups of IgG-crosslinked fatty acid synthetase molecules were isolated by sucrose density gradient centrifugation. Electron microscopic investigation of the crosslinked material as well as other data led us to suggest a three-dimensional model of yeast fatty acid synthetase.