title: Transfer ribonucleic acid dependent but ribosome-independent leucine incorporation into rat brain protein.
abstract: An unusual type of posttranslational modification has been observed in a rat brain in vitro system. It consists in leucine addition to a preformed protein in such a way that the added leucine is not located at either the NH2 or the COOH terminus of the acceptor protein. The incorporation reaction requires ATP, ATP-generating components and tRNA. It is inhibited by aurintricarboxylic acid but does not require the presence of ribosomes or GTP. The incorporated leucine has a free NH2 group, and it is not released by leucine aminopeptidase or carboxypeptidase A. It is linked to the acceptor protein through a bond that is too alkali labile and too hydroxylamine labile to be a peptide bond. The simplest interpretation of the results consists in proposing that an ester bond is formed between the leucine and the side chain of a serine, threonine, or tyrosine in the acceptor protein.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001312:Aurintricarboxylic Acid / Q000494:pharmacology; D001921:Brain / Q000378:metabolism*; D002268:Carboxypeptidases / Q000494:pharmacology; D043422:Carboxypeptidases A; D055598:Chemical Phenomena; D002621:Chemistry; D006160:Guanosine Triphosphate / Q000378:metabolism; D007930:Leucine / Q000378:metabolism*; D007931:Leucyl Aminopeptidase / Q000494:pharmacology; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012343:RNA, Transfer / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012270:Ribosomes / Q000378:metabolism
chemical_list: D009419:Nerve Tissue Proteins; D001312:Aurintricarboxylic Acid; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D012343:RNA, Transfer; D002268:Carboxypeptidases; D007931:Leucyl Aminopeptidase; D043422:Carboxypeptidases A; D007930:Leucine