IDENTIFICATION OF POTENTIAL REDOX-SENSITIVE CYSTEINES IN CYTOSOLIC FORMS OF FRUCTOSEBISPHOSPHATASE AND GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE

Tertiary-structure modeling suggests the occurrence of disulfide bonds in the cytosolic form of fructose-bisphosphatase (EC 3.1.3.11) in spi nach (Spinacia oleracea L.), sugarbeet (Beta vulgaris L.) and potato ( Solanum tuberosum L.). Redox modulation could then control the AMP sen sitivity of fructosebisphosphatase in the cytosol, as suggested by the experiments of E. Khayat et al. (1993, Plant Physiol. 101, 57-64). Mo deling also reveals two cysteine residues correctly positioned to form a disulfide bond and hence potentially redox-sensitive in the cytosol ic glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) from the fac ultative crassulacean metabolism plant Mesembryanthemum crystallinum L .