Activity Ratios of Ribulose-1,5-Bisphosphate Carboxylase Accurately Reflect Carbamylation Ratios 1
AUTOR(ES)
Butz, Nola D.
RESUMO
Activity ratios and carbamylation ratios of ribulose-1,5-bisphosphate carboxylase (RuBPCase) were determined for leaves of Phaseolus vulgaris and Spinacia oleracea exposed to a variety of partial pressures of CO2 and O2 and photon flux densities (PFD). It was found that activity ratios accurately predicted carbamylation ratios except in extracts from leaves held in low PFD. In particular, it was confirmed that the loss of RuBPCase activity in low partial pressure of O2 and high PFD results from reduced carbamylation. Activity ratios of RuBPCase were lower than carbamylation ratios for Phaseolus leaves sampled in low PFD, presumably because of the presence of 2-carboxyarabinitol 1-phosphate. Spinacia leaves sampled in darkness also exhibited lower activity ratios than carbamylation ratios indicating that this species may also have an RuBPCase inhibitor even though carboxyarabinitol 1-phosphate has not been detected in this species in the past.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1055915Documentos Relacionados
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