Catalysis acetoacetate decarboxylase

Primary amine catalysis (usually involving a lysine residue) has been recognised to play an important role in various enzyme-catalysed reactions. Examples are the conversion of acetoacetate to acetone catalysed by acetoacetate decarboxylase, the condensation of two molecules of S-aminolevulinic acid catalysed by -aminolevulinic deshydratase during the biosynthesis of porphyrins, and the reversible aldol condensation of dihydroxy-acetone phosphate with glyceraldehyde which in the presence of aldolase yields fructose-1-phosphate (64) (For reviews see, for example, Snell and Di Mari,... 

Can we apply any of this information from non-enzymatic catalysis to decarboxylating enzymes Some decarboxylases do form Schiff bases with their substrates, and some are dependent on metal ions. The acetone-forming fermentation of Clostridium acetobutylicum requires large amounts of acetoacetate decarboxylase (Eq. 13-44). 

Paracatalytic enzyme modification is a new type of catalysis-linked and, hence, substrate-dependent enzyme modification. In all instances in which the substrate promotes inactivation of an enzyme by a chemical reagent, particularly by an oxidant, paracatalsrtic modification should he considered to be the underlying mechanism. In contrast to ligand-induced and syncatalytic modifications, paracatalytic modification involves a direct chemical interaction between enzyme-activated substrate and extrinsic reagent. In this respect, it is similar to the chemical trapping of covalent enzyme-substrate intermediates, e.g., the reduction of enzyme-substrate Schiff bases by sodium borohydride in class I fructose-l,6-bis-phosphate aldolases - or in acetoacetate decarboxylase. ... 

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