Abstract
Callus from hypocotyl explants of lettuce ( Lactuca sativa L.) was initiated on a modified Murashige and Skoog medium containing 1.0 mg/l of benzyladenine (BA) and naphthaleneacetic acid ( NAA ) .Dihydrofolate synthetase (EC.6.3.2.12) was found in lettuce callus and purified about 36 fold by treating with ethanol and chloroform, ammonium sulfate and gel filtration on Sephadex G-200. The molecular weight of dihydrofolate synthetase was found to be around 40 KD. By Sephadex G-200 column chromatography. The optimum pH for the activity was 6.8 . The optimum reaction temperature was 32C°. The Michaelis constants using dihydropetroic acid and adenosinetriphosphate were 0.036x10-3M and 5.263x10-3M respectively.
