Benzaldehyde lyase, a novel thiamine PPi-requiring enzyme, from Pseudomonas fluorescens biovar I.
Pseudomonas fluorescens biovar I can grow on benzoin as the sole carbon and energy source. This ability is due to benzaldehyde lyase, a new type of enzyme that irreversibly cleaves the acyloin linkage of benzoin, producing two molecules of benzaldehyde. Benzaldehyde lyase was purified 70-fold and found to require catalytic amounts of thiamine PPi (TPP) and a divalent cation as cofactors. Optimal activity was obtained with a 1.0 mM concentration of Mn2+, Mg2+, or Ca2+. Gel permeation chromatography indicated a native molecular weight of 80,000, whereas the enzyme migrated in sodium dodecyl sulfate-containing polyacrylamide gels as a single polypeptide with a molecular weight of 53,000. Benzaldehyde lyase is highly specific; of a variety of structurally related compounds tested, only benzoin and anisoin (4,4'-dimethoxybenzoin) acted as substrates, their apparent Kms being 9.0 x 10(-3) and 3.25 x 10(-2) mM, respectively. A catalytic mechanism for the enzyme is proposed.
González
B
B
Unidad de Microbiología y Genética Molecular, Universidad Católica de Chile, Santiago.
Vicuña
R
R
D000446:Aldehyde-Lyases / Q000302:isolation & purification / Q000378:metabolism*; D001547:Benzaldehydes / Q000378:metabolism*; D001573:Benzoin / Q000378:metabolism; D002384:Catalysis; D002413:Cations, Divalent / Q000378:metabolism; D008970:Molecular Weight; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D013379:Substrate Specificity; D013835:Thiamine Pyrophosphate / Q000378:metabolism*
D001547:Benzaldehydes; D002413:Cations, Divalent; D000446:Aldehyde-Lyases; C059416:benzaldehyde lyase; D001573:Benzoin; D013835:Thiamine Pyrophosphate