Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.
Bioorg Med Chem. 2013 Nov 15;21(22):6915-9. doi: 10.1016/j.bmc.2013.09.032. Epub 2013 Sep 19.
Pheophytinization of chlorophyll (Chl) c1, which was isolated from the diatom Chaetoceros gracilis, was kinetically analyzed under weakly acidic conditions, and was compared with that of protochlorophyllide (PChlide) a and chlorophyllide (Chlide) a. Chl c1 possessing a trans-acrylic acid residue at the 17-position exhibited slower pheophytinization kinetics than PChlide a and Chlide a, both of which possessed a propionic acid residue at the same position. The difference in pheophytinization properties between Chl c1 and (P)Chlide a was ascribable to the electronegativity of the 17-substituent in Chl c1 larger than that of (P)Chlide a due to the C17(1)-C17(2) double bond with the conjugated 17(2)-carboxy group in Chl c1. Demetalation kinetics of PChlide a was slower than that of Chlide a, which originated from the effect of the π-macrocyclic structures.
叶绿素 c1（Chl c1）从硅藻脆杆藻中分离出来，在弱酸性条件下进行了光物理化分析，并与原叶绿素 a（PChlide a）和叶绿素 a（Chlide a）进行了比较。Chl c1 在 17 位具有反式丙烯酸残基，其光物理化转化动力学比具有相同位置丙酸残基的 PChlide a 和 Chlide a 都要慢。Chl c1 和（P）Chlide a 之间光物理化性质的差异归因于 Chl c1 中 17 位取代基的电负性大于（P）Chlide a，这是由于 C17(1)-C17(2)双键与 Chl c1 中共轭的 17(2)-羧基。PChlide a 的脱镁动力学比 Chlide a 慢，这源于π-大环结构的影响。
