Purification and properties of N-formylmethionine aminopeptidase from rat liver.

A specific enzyme for the liberation of N-terminal N-formylmethionine from N-formylmethionyl peptides was purified 4750-fold from rat liver by successive applications of (NH4)2SO4 precipitation, DEAE-cellulose, N-formylbestatin-AH-Sepharose 4B and AH-Sepharose 4B chromatography followed by Sepharose CL-6B gel filtration. The molecular weight was determined by gel filtration on Sepharose CL-6B as 29 000 ± 5000. This was suggested to be a tetramer consisting of a subunit which was shown by sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis to have a 72 000 ± 2000 molecular weight.