Structural, thermal and enzymatic analysis of naturally occurring and D-amino acid substituted peptides

Designing of new peptide materials for biomedical and protein engineering applications are important. In the present work an attempt has been made to study the effect of D-Leu in collagen like tetra peptide on the structure and stability of peptide against enzymes and results are compared with its chiral counterpart L-form. Effect of replacement of L-Leu in Leu-Gly-Pro-Ala tetra peptide with D-Leu on structure has been studied using circular dichroic spectroscopy (CD). Our findings suggest that, D-Leu substitution leads to conformational changes in Leu-Gly-Pro-Ala secondary structure from β-sheet to turns. L → D-Leu Configurational changes in Leu-Gly-Pro-Ala owes to enhanced thermal stability which has been substantiated through CD and differential scanning calorimetry. Change in chirality of the leucine inhibits collagenolytic activity, which enables to design selective inhibition of proteases with greater specificity.

限制铬鞣过程中的用水量

工业生产如铬鞣常常需要耗费大量的水，导致全球需求的宝贵资源枯竭。而在胶原基质中铬的水解、扩散、分布和固定，水是必须的。虽然可以通过使用绿色溶剂如生物乙醇使铬鞣所需水量达到最小来获得比较绿色和可持续的解决方案，但这一问题已争议了数年。本研究通过冻干技术显示，对于铬鞣使胶原基质内部含水量最低55％～65％是必须的。通过光学和电子显微镜分析结合x一射线能谱分析证实，随着冷冻时间的延长，皮基质内含水量从65％降低到15％，铬在革中的含量与分布呈线性降低。