Variation in the Specificity Factor of C3 Higher Plant Rubiscos Determined by the Total Consumption of Ribulose-P2

The specificity factors for ribulose 1, 5-bisphosphate carboxylase/oxygenase(rubisco) from six species of photosynthetic organisms are compared.The values were determined by measuring the oxygen uptake duringthe total consumption of ribulose-P₂ in the presence of variousconcentrations of O₂ and CO₂. The specificity factors determinedin this way were similar to values previously published; smallbut significant differences were found between the specificityfactors of rubisco from C₃ higher plant species. Key words: Specificity factor, total consumption, partitioning, carboxylase oxygenase ratios, ribulose bisphosphate carboxylase, rubisco