Enzymatic synthesis of 3,4-dihydroxyphenyl-L-alanine by free and immobilized Citrobacter freundii cells
Voĭvodov, K.I.; Tysiachnaia, I.V.; Gubnitskiĭ, L.S.; Iakovleva, V.I.; Berezin, I.V.
Prikladnaia Biokhimiia i Mikrobiologiia 21(2): 161-166
1985
ISSN/ISBN: 0555-1099 PMID: 3921951 Document Number: 248026
The Citrobacter freundii 62 cells immobilized in PAAG and possessing the tyrosine-phenol-lyase (TPL) activity catalyse the synthesis of 3,4-dihydroxyphenyl-L-alanine (DOPA) from pyrocatechol and ammonium pyruvate. The synthesis of DOPA was studied using both free and immobilized bacterial cells. When the concentration of pyrocatechol is over 0.1 M the TPL activity of the cells is inhibited. The concentration of pyrocatechol can be increased up to 0.3 M by using an equimolar mixture of pyrocatechol and boric acid. The addition of ascorbic acid as an antioxidant results in a lower TPL activity of both free and immobilized bacterial cells.