Complete amino acid analysis of peptides and proteins after hydrolysis by a mixture of sepharose-bound peptidases.
Incubation with a mixture of Sepharose-bound peptidases was shown to result in the quantitative release of amino acids from certain peptides and S-aminoethylated proteins. Subtraction of the low background values of amino acids generated by the enzymes enables amino acid ratios of corticotrophin-(1-24)-tetracosapeptide to be determined with a standard deviation on repeat digestions of 3-5%. Good values were obtained for amino acids that are completely or partially destroyed on acid hydrolysis, i.e. tryptophan, tyrosine, serine, asparagine and glutamine. Experiments with peptides containing d-amino acids showed that the enzyme mixture is stereospecific and could therefore be used to detect the presence of d-residues in peptides. The enzyme mixture completely hydrolyses peptide fragments obtained after Edman degradation and should therefore be useful for determining sequences of peptides containing acid-labile amino acid residues. The activities of the bound enzymes were unaltered over a period of 7 months and they provide a simple, reproducible procedure for the quantitative determination of amino acids in peptides and proteins containing l-amino acids.
D000324:Adrenocorticotropic Hormone / Q000032:analysis; D000596:Amino Acids / Q000032:analysis*; D000626:Aminopeptidases; D000804:Angiotensin II / Q000032:analysis; D001920:Bradykinin / Q000032:analysis; D002918:Chymotrypsin; D004150:Dipeptidases; D006868:Hydrolysis; D009113:Muramidase / Q000032:analysis; D010447:Peptide Hydrolases; D010455:Peptides / Q000032:analysis*; D011134:Polysaccharides; D011485:Protein Binding; D011506:Proteins / Q000032:analysis*; D012260:Ribonucleases / Q000032:analysis; D014357:Trypsin
D000596:Amino Acids; D010455:Peptides; D011134:Polysaccharides; D011506:Proteins; D000804:Angiotensin II; D000324:Adrenocorticotropic Hormone; D012260:Ribonucleases; D009113:Muramidase; D010447:Peptide Hydrolases; D000626:Aminopeptidases; D004150:Dipeptidases; D002918:Chymotrypsin; D014357:Trypsin; D001920:Bradykinin