Protoheme Turnover and Chlorophyll Synthesis in Greening Barley Tissue 1
AUTOR(ES)
Castelfranco, Paul A.
RESUMO
Studies in which 14C-labeled precursors were fed to etiolated barley leaves (Hordeum vulgare L. var. Proctor) yielded chlorophyll and protoheme having similar specific radioactivities. These findings indicate: (a) there appears to be a rapid turnover of protoheme in the absence of net synthesis; (b) both pigments probably originate from a single 5-aminolevulinic acid pool; (c) the efficient utilization of glutamate-1-14C and the relatively poor utilization of glycine-2-14C suggest that 5-aminolevulinic acid is probably synthesized by a pathway other than 5-aminolevulinic acid synthetase (succinyl CoA-glycine succinyltransferase) in agreement with previously published work; (d) protoheme turnover appears to be faster under conditions which allow for rapid chlorophyll accumulation; (e) difference spectra indicate that mitochondrial cytochromes make a relatively minor contribution to the total heme in barley leaves. These findings are discussed in the light of current knowledge about tetrapyrrole regulation in photosynthetic organisms.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=541643Documentos Relacionados
- Phytochrome Regulation of Greening in Barley—Effects on Chlorophyll Accumulation 1
- Controls on Chlorophyll Synthesis in Barley 1
- Cryopreservation of Chlorophyll Synthesis and Apoprotein Stabilization in Barley Etioplasts.
- Light-induced de Novo Synthesis of Ribulose 1,5-Diphosphate Carboxylase in Greening Leaves of Barley
- Accumulation of δ-Aminolevulinic Acid and Its Relation to Chlorophyll Synthesis and Development of Plastid Structure in Greening Leaves 1