Table 4.

Summary of sensitivity to feedback inhibition by branched chain amino acids of AHAS of purified resistant populations, relative to that of the S populations (refer to Figs 3–4)

Population	Valine	Leucine	Isoleucine
Group I
R-197-Gln	No change	No change	No change
Group II
R-197-Ala	Slightly decreased	No change	Slightly decreased
R-197-Ser	Slightly decreased	No change	Slightly decreased
R-574-Leu	Slightly decreased	No change	No change
Group III
R-197-Arg	Increased	Increased	Increased