D-Tyrosine Metabolism in Sorghum vulgare Seedlings

Abstract

IT has previously been reported that sorghum seedlings incorporate carbon-14 from DL-tyrosine-2-¹⁴C into the nitrile carbon of p - hydroxymandelonitrile - β - glucose¹. Furthermore, it was demonstrated that ¹⁴C from D-tyro-sine-2-¹⁴C was not incorporated into p -hydroxymandelonitrile-β-glucose¹. It was also shown that a radioactive material which migrated differently from either the glucoside or tyrosine could be extracted from seedlings allowed to metabolize either DL-tyrosine-2-¹⁴C or DL-tyrosine-3-¹⁴C. Similar experiments with L-tyrosine-¹⁴C did not yield appreciable radioactive material in this portion of the chromatogram. These preliminary experiments suggested that D-tyrosine metabolism in Sorghum vulgare seedlings may not be affected through either a deamination or racemization as either process would lead to precursors of p-hydroxymandelonitrile-β-glucose^1,2.