Studies on the Biosynthesis of Protochlorophyllide Ester in Etiolated and Green Tissues of Higher Plants
Cucumber cotyledons incubated in darkness with (alpha),(alpha)'-dipyridyl and (delta)-aminolevulinic acid (ALA) accumulated a pigment which had the spectroscopic properties of Mg-protoporphyrin monomethyl ether (MPE) but physical properties similar to those of protochlorophyllide (Pchlide) ester. When this compound was subjected to demetallation and acid hydrolysis the resulting porphyrin had the chromatographic and spectral properties of protoporphyrin (Proto). This new pigment appears to be a fully esterified MPE. Analysis of the MPE-like pigment preparation by HPLC revealed four peaks which were all spectrally identical to MPE. These pigments probably differed in mobility due to different esterifying alcohols. Analysis of the alcohols bound to cucumber MPE ester indicate that phytol is not present. Similar results were obtained when Pchlide ester preparations were analyzed.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign