FIG. 1.

¹H NMR spectra of cis-dienelactone and transformation products. cis-Dienelactone (2 mM) in 50 mM phosphate buffer (pH 7.4) (A) was incubated for 1 h with partially purified dienelactone hydrolase (43 mU/ml) (B), acidified to pH 2.5 (C), and kept under acidic conditions for 48 h (D), and the resulting solution was neutralized (E). (F) ¹H NMR spectrum of cis-dienelactone after 1 h of incubation with partially purified dienelactone hydrolase (29 mU/ml) plus partially purified maleylacetate reductase (71 mU/ml). The proposed solution structures cis-dienelactone (A), 3-oxo-cis-4-hexenedioate (maleylacetate) (B), 4-carboxymethyl-4-hydroxybut-2-en-4-olide (4-hydroxymuconolactone) (C), cis-acetylacrylate acylal (D), cis-acetylacrylate (E), and 3-oxoadipate (F) are indicated.