The Action of Blue Light on 5-Aminolevulinic Acid Formation

Abstract

In most angiosperms the last step in chlorophyll biosynthesis, the conversion of proto-chlorophyll(ide) to chlorophyll(ide), requires light. In recent years, however, it has been found in several organisms that the first step, the formation of 5-aminolevulinic acid (ALA), is also light-dependent. The formation of ALA is not only the first step in the biosynthesis of tetrapyrroles but is also a rate-limiting step and plays a key role in the regulation of tetrapyrrole biosynthesis. Thus the light dependence of this step may be of considerable importance in the biosynthesis not only of chlorophyll but also of hemes, corrins, and bile pigments including the photomorphogenetically active plant pigment phytochrome. The light dependence of ALA formation has been reported in many higher plants but only in a few cases have investigations been made about the photoreceptor involved and those suggest the participation of phytochrome (Masoner and Kasemir 1975). Among the photosynthetic microorganisms, light-dependent ALA formation has been reported for Chlorella fusca (Porra and Grimme 1974), Chlorella sp. (Beale 1971), Chlorella vulgaris (Melier and Harel 1978), Chlorella protothecoides (Oh-hama and Senger 1978), Scenedesmus obliquus (Oh-hama and Senger 1975; Klein and Senger 1978a), Euglena gracilis (Salvador et al. 1976) and Rhodopseudomona spheroides (Lascelles 1968); however, only in Chlorella protothecoides and Scenedesmu obliquus has the wavelength dependence of ALA formation been more intensively studied.KeywordsAction SpectrumMonochromatic LightEuglena GracilisScenedesmus ObliquusChlorophyll FormationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.