氨基酸组成及溶剂环境对淡水鱼胶原蛋白热稳定性能的影响

本文探讨了氨基酸组成、分布以及溶剂环境对鱼源胶原蛋白蛋白热稳定性能的影响。利用不同鱼类的胶原蛋白为实验样本,测定胶原蛋白氨基酸组成和热变性温度,通过相关性分析明确了影响胶原蛋白热变性温度的主要氨基酸种类和分布指标。结果表明,胶原蛋白中脯氨酸羟基化率、碱性氨基酸、带电荷极性氨基酸和总极性氨基酸含量与胶原蛋白热变性温度呈正相关,而亚氨基酸与非极性氨基酸含量与胶原蛋白热变性温度呈负相关(p0.01)。运用逐步多元回归分析方法,建立了脯氨酸羟基化率和带电荷极性氨基酸与胶原蛋白热变性温度之间的相关性数学模型,经验证,该模型能较好的预测鱼源胶原蛋白的热变性温度。在此基础上,进一步研究了胶原蛋白所处溶剂环境对其热稳定性能的影响。结果表明,提高水分子浸润胶原蛋白程度和体系离子强度,或降低体系pH均会显著降低胶原蛋白热稳定性能。

Effects of Amino Acid Composition and Solvent Environment on the Thermal Stability of Fish Collagen

Collagen was extracted from different species of grass carp and used to study amino acid compositions and thermal stability. The result of a correlation analysis between the amino acid compositions and denaturation temperatures of various collagens showed that the degree of hydroxylation of proline, the content of alkaline amino acids, polar amino acids with charge, and total polar amino acids were positively correlated with the denaturation temperature for collagen. However, the content of imino acids and nonpolar amino acids showed an inverse correlation with the denaturation temperature (p < 0.01). The mathematical model of correlation between amino acid distribution and denaturation temperature of collagen was established by step-wise regression analysis using SAS software, which accurately forecasts the denaturation temperature of fish collagen. At the same time, the influence of solvent environment, including infiltration degree of water, pH, ionic strength, and ion species, on the thermal stability of fish collagen was investigated. The results showed that the thermal stability of fish collagen underwent a remarkable decrease with increase in the infiltration degree of water and ionic strength as well as a decrease in pH of the solvent.