||p.424 2nd paragraph:"The similar CO2 compensation concentration values in C3 plants (refs 10, 11) and C02/02 specificity found in all C3 Rubisco enzymes examined thus far (ref 18, refs 55, 56 beneath table, Table 1) indicates that there is little if any genetic variation in the photosynthesis/photorespiration ratio in these species except for that arising from differences in stomatal conductance, which alters the internal C02/02 ratio." p.434 2nd paragraph:"Absolute values for the C02/02 substrate specificity were determined by plotting the ratio of the two activities as a function of the ratio of the two substrates. From Equation 1, the slope of this line equals VcKo/VoKc, the C02/02 substrate specificity. The specificity value for the single subunit-type Rubisco from Rhodopseudomonas sphaeroides, a photosynthetic bacterium, was 9 (Table 1). The specificity value increased to about 50 in cyanobacterial Rubisco, 54 in the enzyme from Euglena, 62 in enzymes from unicellular green algae, and about 80 for C3 plants."