Interaction of tyrosine phenol-lyase with phosphoroorganic analogues of substrate amino acids

The phosphinic analogues of tyrosine and pyruvate were first demonstrated t o be substrates in the reactions of elimination and synthesis catalyzed by tyrosine phenol-lyase. Kinetic parameters of the enzymatic process were det ermined, and the first enzymic synthesis of an aminophosphinic acid was car ried out. Replacement of the planar HOOC-group by the tetrahedral (HO)(O)PH -group in the substrate slightly affected its affinity for the enzyme but s ubstantially diminished the conversion rate. For phosphonic analogues, cont aining (HO)(2)(O)P group, the affinity to the enzyme was decreased consider ably while the conversion was completely prevented. Thus, the structural pa rameters of the acid group are important not only for the affinity for the enzyme, but also for the formation of the catalytically competent conformat ion of the active site.