Analysis of cDNA clones encoding sucrose-phosphate synthase in relation to sugar interconversions associated with dehydration in the resurrection plant Craterostigma plantagineum Hochst.
AUTOR(ES)
Ingram, J
RESUMO
Sucrose-phosphate synthase (SPS) is a key enzyme in the regulation of sucrose metabolism, being responsible for the synthesis of sucrose 6-phosphate from fructose 6-phosphate and uridine 5'-diphosphate-glucose. We report on the isolation and characterization of cDNA clones encoding SPS from Craterostigma plantagineum Hochst., a resurrection plant in which the accumulation of sucrose is considered to play an important role in tolerance to severe protoplastic dehydration. Two distinct classes of cDNAs encoding SPS were isolated from C. plantagineum, and are represented by the clones Cpsps1 and Cpsps2. The transcripts corresponding to both cDNAs decrease to very low levels in dehydrating leaves of C. plantagineum. Only the Cpsps1 transcript occurs in the roots, where it is present at a higher level than in leaves and increases upon dehydration of the plant. Higher enzymatic activities have been determined in protein extracts of dehydrated tissues compared with untreated tissues, which correlates with an increase in protein levels. It is suggested that the overall regulation of SPS is strongly influenced by the changing composition of the cytoplasm in C. plantagineum leaves during the dehydration-rehydration cycle.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=158466Documentos Relacionados
- Physical and Kinetic Evidence for an Association between Sucrose-Phosphate Synthase and Sucrose-Phosphate Phosphatase.
- Elevated Levels of Both Sucrose-Phosphate Synthase and Sucrose Synthase in Vicia Guard Cells Indicate Cell-Specific Carbohydrate Interconversions.
- Kinetic Characterization of Spinach Leaf Sucrose-Phosphate Synthase 1
- Biosynthesis of Sucrose and Sucrose-Phosphate by Sugar Beet Leaf Extracts 1
- Purification and Preliminary Characterization of Sucrose-Phosphate Synthase Using Monoclonal Antibodies 1