The Comparison of Free and Bound Amino Acids between Dry and Wet Types of Cerumen

Abstract

1) The wet and dry types of normal cerumens obtained from healthy Japanese children at seven to twelve years of age were fractionated into the following four fractions according to the authors' procedure: Fractions I, II, III and IV were composed mainly of lipid, an unknown substance tentatively termed ‘substance X’, free amino acids and protein, respectively.
2) Identification and estimation of free amino acids in fractions II and III were made by means of ninhydrin reaction and dinitrophenylation, and bound amino acids of protein moiety of Fraction IV were determined after acid hydrolysis.
3) The content of free amino acids was four times higher in the dry type of cerumen than in the wet type: it was 15 and 4 per cent for the dry and wet types, respectively.
4) Following 18 kinds of amino acid were identified commonly in the both types of cerumen, and no qualitative difference was seen between them: leucine, isoleucine, phenylalanine, valine, tryptophan, tyrosine, alanine, threonine, glycine, serine, glutamic and aspartic acids, glutaxnine, eystine, lysine, arginine, citrull ine and proline.
5) In the Fraction IV of the both types, 15 amino acids were identified as follows: Ieucine, isoleucine, phenylalanine, valine, tryptophan, tyrosine, alanine, threonine, gycine, serine, glutamic and aspartic acids, cystine, lysine, and proline. No qualitative and quantitative differences were observed between the two types of the cerumen.