Chloroplast biogenesis: Quantitative determination of monovinyl and divinyl Mg-protoporphyrins and protochlorophyll(ides) by spectrofluorometry

Abstract

General equations which permit the determination of the amounts of any two closely related fluorescent compounds which can be distinguished by 77°K but not by 293°K spectrofluorometry have been described. This was achieved in the presence or absence of a third interfering compound, without prior separation of the fluorescent species. The adaptation of the generalized equations to the determination of the amounts of monovinyl (MV) and divinyl (DV) Mg-protoporphyrins or of MV and DV protochlorophyll(ides) in the presence or absence of Mg-Protos [Mg-protoporphyrin IX (Mg-Proto), Mg-Proto monoester, Mg-Proto diester or a mixture of those three tetrapyrroles] interference, was then demonstrated over a wide range of MV DV tetrapyrrole proportions. These equations are likely to be very useful for the study of the intermediary metabolism of the monovinyl and divinyl chlorophyll biosynthetic routes in plants.