Abstract
With the use of low temperature spectrofluorometry and matrix calculations it was demonstrated that the chlorophyll
a pool of higher plants is made up of four different chlorophyll
a chromophores. The latter were segregated by high pressure liquid chromatography on a silica column. They were designated Chl
a (E432 F664), Chl
a (E436 F670), Chl
a (E443 F672) and Chl
a (E446 F674), where E refers to the Soret excitation maximum and F to the fluorescence emission maximum at 77 K in ether. Likewise the Chl
b pool was shown to consist of at least four different Chl
b chromophores which were designated: Chl
b (E465), Chl
b (E470), Chl
b (E475) and Chl
b (E485). It was proposed that the various chlorophyll chromophores differed by the degree of oxidation of their side chains at the 2 and 4 positions of the macrocycle. It was also suggested that the chemical modifications at the 2 and 4 positions of the macrocycle may play an important role in positioning the different chlorophyll chromophores in the thylakoid membranes.