ALCOHOL-DEHYDROGENASE ISOENZYMES FROM NICOTIANA-TABACUM INCLUDE ADH OF BOTH NICOTIANA-SYLVESTRIS AND N-TOMENTOSIFORMIS

Electrophoretic separation of seed alcohol dehydrogenase (ADH) from Ni cotiana tabacum on 12% starch gels at pH 7.8 produced only one band wi th an apparent R(f) of 0.65, which confirmed earlier reports. The same was found with pollen ADH. However, in polyacrylamide gel isoelectric focusing, seed ADH separated into three distinct bands with apparent pI of 5.33, 5.42 and 5.50. The pl 5.33 isoenzyme was found to be the e ssential form in N. sylvestris seeds. The analysis of charge propertie s of N. tomentosiformis seed ADH showed only one isoenzyme with pI of 5.56. These results present further evidence that N. tabacum has arise n from a cross between a N. sylvestris predecessor and an ancestral ty pe of N. tomeniosiformis. The presence of the pI 5.42 form in N. tabac um is consistent with the reported formation of heterodimeric ADH in t obacco hybrids.