(浙江大学化学系 杭州 310027)

采用RD-496Ⅱ型精密微量热量计分别测定了甘氨酸、L-丙氨酸、L-丝氨酸、L-苏氨酸、甘氨酰甘氨酸和甘氨酰甘氨酰甘氨酸在纯水以及不同浓度甘露醇、山梨醇和肌醇水溶液中的溶解焓, 计算了这些氨基酸和肽从水到3种多元醇溶液中的迁移焓. 实验发现, 氨基酸和肽从水到多元醇溶液中的迁移焓均为负值, 且随多元醇浓度的增加而减小. 根据共球交盖模型分析了水溶液中氨基酸和肽分子与多元醇分子间的相互作用.

Enthalpies of solution of glycine, L-alanine, L-serine, L-threonine, diglycine, and triglycine were measured in water and aqueous solutions of D-mannitol, D-sorbitol and inositol at 298.15 K by an RD-496 II microcalorimeter. Enthalpies of transfer of these amino acids and glycine peptides from water to aqueous polyol solutions were calculated. It was shown that the enthalpies of transfer had negative values in the investigated concentration range, and decreased with increasing the concentration of polyol. The interactions of the amino acid or glycine peptide molecules with polyol molecules were analyzed and explained from the co-sphere model.