THE EFFECT OF pH ON THE INCORPORATION OF AMINO ACIDS INTO HUMIC ACID EXTRACTED FROM SOIL

The effect of pH on the incorporation of six ¹⁴C-labelled amino acids and a dipeptide into humic acid extracted from a podzolic soil was examined. Maximum incorporation was found to occur at a pH which coincided with the apparent dissociation constants of their α-amino groups. Incorporation took place, into forms which were both acid-hydrolysable and non-hydrolysable, the latter accounting for between ten and twenty per cent of the total.