A cDNA clone for the human skeletal-muscle fatty-acid-binding protein (FABP) was isolated by screening of a human adult muscle lambda gt11 expression library with an anti-(muscle FABP) serum. The identify of the clone was confirmed by transcription/translation in vitro in plasmid pSP6.5, followed by immunoprecipitation. The nucleotide sequence of the 551 bp cDNA insert showed an open reading frame of 399 nucleotides, coding for a protein of 133 amino acid residues with a calculated molecular mass of 14858 Da and a pI of 4.94. Only one cysteine residue was found, at position 125. Peptide sequence analyses of human skeletal-muscle and heart FABP, after carbamoylmethylation and lysyl endopeptidase digestion followed by automatic Edman degradation, showed that both proteins are identical. No evidence was found for the existence of isoproteins in muscle. The chromosomal localization of the human muscle FABP gene was determined by analysing 31 human x rodent somatic-cell hybrid lines. The human muscle FABP gene could be assigned to chromosome 1pter-q31.
