Details

Autor(en) / Beteiligte

• Crawford, M S
• Wang, W Y

Titel

Metabolism of magnesium protoporphyrin monomethyl ester in Chlamydomonas reinhardtii [Algae]

Ist Teil von

• Plant physiology (Bethesda), 1983-02, Vol.71 (2), p.303-306

Ort / Verlag

United States: American Society of Plant Physiologists

Erscheinungsjahr

1983

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The y-1 mutant of Chlamydomonas reinhardtii is defective in the conversion of protochlorophyllide (Pchlide) to chlorophyllide in the dark. Aerobic δ-aminolevulinic acid (ALA) feeding of y-1 cells causes protoporphyrin monomethyl ester (PME) to accumulate in addition to increased levels of Pchlide. y-1 cell homogenates are not capable of methylating protoporphyrin (PROTO) to form PME but can methylate magnesium protoporphyrin (MgP) to form magnesium protoporphyrin monomethyl ester (MgPME). Anaerobic ALA feeding of y-1 causes concomitant accumulation of PME and MgPME. y-1 cells treated with α,α′-dipyridyl (DP) accumulate MgPME but not PROTO or PME. A mutant strain (bme) of Chlamydomonas has been isolated which has very little chlorophyll and accumulates PME. bme Cell homogenates can methylate MgP but not PROTO. We propose that: (a) in Chlamydomonas, PME is the initial breakdown product of MgPME; (b) both the breakdown of MgPME to PME and the conversion of MgPME to Pchlide require O2; (c) the breakdown of MgPME to PME appears to require Fe; and (d) the PME accumulated in the bme mutant is the result of an increased breakdown of MgPME.