ISSN:
1573-5079
Keywords:
adaptation
;
biosynthesis
;
bacteriochlorophyll a formation
;
3-acetyl group formation
;
chlorophyll b formation
;
degradation
;
7-formyl group formation
;
isocyclic ring E formation
;
oxygenase- and hydratase-catalysed cyclization
;
origin of 133- and 173-carboxyl groups
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Chlorophylls, magnesium-containing tetrapyrrolic pigments of photosynthesis, are widely-distributed in Nature and participate in both light harvesting and in the transduction of light energy to chemical energy for the photosynthetic fixation of carbon dioxide. We briefly discuss the extensive role of various isotopic labelling techniques in elucidating the pathway of tetrapyrrole-pigment biosynthesis and we acknowledge the classic and meticulous research of David Shemin who, approximately 50 years ago, introduced isotopic tracer techniques with 15N and 14C isotopes to study the biosynthesis of the carbon/nitrogen macrocycle of haem, an iron tetrapyrrole. The main focus of this review is the application of mass spectrometry and 18O labelling to the study of the incorporation of oxygen atoms from molecular oxygen or water into the periphery of the chlorophyll macrocycle during biosynthesis and their loss during degradation and light acclimation. In particular, we review the mechanism of formation of the isocyclic ring of chlorophylls, in higher plants, green algae and various photosynthetic bacteria, which concomitantly incurs formation of the 131-oxo group that is present in all photosynthetically-active chlorophylls. In addition we discuss the formation of the ubiquitous 133- and 173-carboxyl groups and also the formation of the 7-formyl group of chlorophyll b and the 3-acetyl group of bacteriochlorophyll a.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1010631505071
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