@article {49877,
	title = {Changes in Amino Acids Content in Humic Acids Repetitively Extracted From Peat And Sod-Podzolic Soils},
	journal = {Canadian Journal of Soil Science},
	volume = {94},
	year = {2014},
	pages = { 575-583},
	abstract = {<p>Amino acids (AAs) and peptides are thought to be part of humic acids (HAs) but debate whether they are an integral part of the HAs is still going. Humic acids sequentially extracted from peat and sod-podzolic soil were analyzed for their AAs content, elemental composition and by FTIR spectroscopy. Extracted HAs were hydrolyzed in 6 M HCl for 16 h for AAs release, which was detected by capillary electrophoresis system. Alanine, arginine, sum of aspartic acid and asparagine, sum of cysteic acid and cysteine, sum of glutamic acid and glutamine, glycine, histidine, leucine and isoleucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine, valine were identified. The total content of hydrolysable AAs in sod-podzol HAs increased by 6.2{\textendash}8.2\% with increasing the extraction cycles while an inverse tendency was observed for AAs released from peat HAs. Moreover, individual AAs expressed as percentages of total AAs were constant values with coefficients of variation lower than 20\% for the studied HAs.</p>
},
	url = {http://pubs.aic.ca/doi/abs/10.4141/CJSS2013-064},
	author = {E. A. Vialykh and S. A. Ilarionov and H.M. Abdelrahman and I. A. Vialykh}
}
