Growth and Production of Steroidal Sapogenins and Glycoalkaloids in Solanum jasminoides Paxt., Suspension Cultures

Fumarate reductase was highly purified from the cytosol fraction of the cells of baker’s yeast, which were anaerobically cultured, with a yield of 6% by .7 steps. The purified enzyme is homogeneous in disc-gel electrophoresis, and has a molecular weight of 58,800. Its isoelectric point is 5.3. The enzyme contains 1 molecule of non-covalently bound FAD per molecule of protein. Non-heme iron was not detected. The amino acid composition was determined. The spectra of the enzyme showed absorption peaks at 273, 380 and 456 nm with shoulders at 370, 440 and 478 nm. The fluorescence spectra showed excitation peaks at 452 and 368 nm and an emission peak at 500 nm. Double-reciprocal plots of the reaction rate against the FADH₂ and FMNH₂ concentrations curved upwards. The hill coefficient values and S_0.5 for FADH₂ and FMNH₂ were estimated to be 1.6 and 0.21 µm, and 1.5 and 0.38 µm, respectively. The Km for fumarate was 0.2 mm.