The dilution enthalpies of L-alanine in sucrose-water mixed solvents at 298.15 K were measured by using LKB2277 flow microcalorimetry. Using the McMillan-Mayer theory, the enthalpic pair interaction coefficients (h_2) of alanine over the whole range of sucrose-water mixed solvents have been calculated and compared with the enthalpic pair interaction coefficients of alanine in glucose- water mixed solvents. It is found that h_2 alanine passes through a maximum at molar fractions 0.05843 and 0.1009 of sucrose and glucose respectively. The position of maximum of h_2 is is related to the number of the hydroxyl groups. The results are discussed n terms of solute-solute and solute-solvent interactions.

Key words: alanine, sucrose, BIOLOGICAL ACTIVITY, INTERACTIONS, GLUCOSE, WATER