Determination of amino acids in soils of the 'Cerrado'

Abstract

This study aims to identify the amino acids present in soils of the Distrito Federal (Brazil). The peptides were extracted from the soils using water at 100^o C for 10 hours and afterwards separated by permeation in gel (Sephadex G-50). The amino acids occurred in the following ranges: glycine - 18.42 to 180.29 nmol/g (average - 104.98 nmol/g); alanine - 9.18 to 218.77 nmol/g (average - 92.08 nmol/g); serine - 17.43 to 147.53 nmol/g (average - 60.49 nmol/g); phenylalanine - 12.87 to 192.40 nmol/g (average - 60.04 nmol/g); proline - 28.42 to 123.64 nmol/g (average - 56.80 nmol/g); glutamic acid - 19.14 to 148.67 nmol/g (average - 52.40 nmol/g); threonine - 9.41 to 127.74 nmol/g (average - 51.32 nmol/g); valine - 10.54 to 119.65 nmol/g (average - 45.40 nmol/g), leucine - 5.54 to 96.69 nmol/g (average - 45.25 nmol/g); cysteine - 7.00 to 96.88 nmol/g (average - 41.00 nmol/g); aspartic acid - 10.97 to 111.89 nmol/g (average - 35.27 nmol/g); tyrosine - 5.74 to 98.77 nmol/g (average - 31.83 nmol/g); isoleucine - 10.18 to 56.68 nmol/g (average - 28.68 nmol/g); methionine - 6.21 to 21.74 nmol/g (average - 13.98 nmol/g); histidine - 5.18 to 23.30 nmol/g (average - 10.09 nmol/ g); arginine - 6.09 to 10.13 nmol/g (average - 8.01 nmol/g) and lysine - 1.32 to 10.56 nmol/g (average - 4.09 nmol/g). The average composition of amino acids in soils of "Cerrado" region showed a predominance in the neutral and acidic amino acids. Glycine, alanine, serine, aspartic acid and glutamic acid were found in all of the 20 soils analysed.