Stereochemistry of 4-carboxymuconolactone decarboxylase and muconolactone isomerase in the. beta. -ketoadipate pathway

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5179582

Whitman, C P; Chari, R V.J.; Ngai, K L; Kozarich, J W

The protocatechuate and catechol pathways, two separate and parallel branches of the ..beta..-ketoadipate pathway in Pseudomonas putida, converge at a common intermediate - ..beta..-ketoadipate enol-lactone. The enol-lactone is generated by 4-carboxymuconolactone decarboxylase in the protocatechuate pathway while muconolactone isomerase produces it in the catechol pathway. The presence of these enzymes as well as ..beta..-carboxymuconate cycloisomerase and its substrate, ..beta..-carboxy-cis,cis-muconate, in a NMR tube, leads to the following sequence of events. Lactonization of ..beta..-carboxy-cis,cis-muconate produces 4-carboxymuconolactone which decarboxylates enzymatically with deuteration by D/sub 2/O to afford 2-(/sup 2/H)-4-ketoadipate enol-lactone - the substrate for muconolactone isomerase. Further conversion of the monodeuterated enol-lactone by muconolactone isomerase affords muconolactone which is nearly completely deuterated at the 4 position. The proton ricochets between the 2 and 4 positions with concurrent washout while in the 2 position. Based on the known absolute stereochemistry of 4-carboxymuconolactone and muconolactone, these results suggest that both the decarboxylase and isomerase proceed by syn mechanisms, but operate on opposite faces of the common enol-lactone substrate.

• Research Organization: Univ. of Maryland, College Park
• OSTI ID: 5179582
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
DECARBOXYLASES
STEREOCHEMISTRY
ISOMERASES
BIOLOGICAL PATHWAYS
DEUTERIUM
NMR SPECTRA
PSEUDOMONAS
TRACER TECHNIQUES
BACTERIA
CARBON-CARBON LYASES
CARBOXY-LYASES
ENZYMES
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LYASES
MICROORGANISMS
NUCLEI
ODD-ODD NUCLEI
SPECTRA
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques
550600 - Medicine