Cysteine-glucose mixture products

Dawes and Edwards (1966) isolated it from the volatiles obtained by heating a mixture of D-fructose and glycine or L-3-phenylalanine. Wang et al. (1969) presented a model reaction in which the product of condensation of pyruvaldehyde with any amino acid degraded by a Strecker reaction can form an aminoketone which by subsequent steps of self-condensation and oxidation formed 2,5-dimethylpyrazine (Wang et al., 1969 Manley et al., 1974). It was found in a heated cysteine/glucose model system (Sheldon et al., 1986). 

In contrast to the system of Shimura et al. (1964), intact protoplasts of strain 10716 require six amino acids for production of bacitracin and, for maximal yield, glucose is needed. Disrupted protoplasts are unable to synthesize the antibiotic (Snoke, 1961). With protoplasts, the six needed amino acids are L-cysteine, L-isoleucine, L-leucine, L-histidine, L-ornithine, and L-asparagine. Neither D-orni-thine nor D-asparagine can be utihzed directly and D-phenylalanine inhibits formation of bacitracin in the absence of L-phenylalanine. A peptide factor in soybean was found to be stimulatory for synthesis of bacitracin by whole cells provided that D-phenylalanine is present in the reaction mixture (Snoke, i960, 1961). In the absence of the D-amino acid, the peptide factor is inactive. 

---