A Study of the Hydrogenlyase Reaction With Systems Derived From Normal and Anaerogenic Coli-Aerogenes Bacteria

Formate is anaerobically decomposed to molecular hydrogen and carbon dioxide by many coli-aerogenes bacteria according to the equation: HCOOH C0 + H2 The mechaDism of this process, i. e., the hydro-genlyase reaction, has been the subject of con-siderable research and speculation over several decades. One fundamental aspect of the reaction which has received particular attention is the question of whether one or more enzymes are required for the conversion. It seems reasonable that definitive and unambiguous evidence relat-ing to this point will necessaily require detailed analysis of the system in the cell-free state. A number of properties of the cell-free system (Gest, 1952; Barkulis and Gest, 1953) and the available results of growing and resting cell ex-periments were recently reviewed in detail by one of the present authors (Gest, 1954), who con-cluded that formate is decomposed to H2 and C02 by a multienzyme system containing "formic dehydrogenase " and hydrogenase. The concept that the hydrogenlyase reaction requires a series of catalysts which may be represented as: formicdehydrogenase.... carriers.... hydrogenase hydrogenlyase was also supported by the early experiments of Ordal and Halvorson (1939) who investigated the distribution of formic dehydrogenase, hydro-genase, and hydrogenlyase activities in intact celLs of normal Escherichia coli and several anaerogenic variants. The present study of hydrogen metabolism in ceU-free systm derived from normal E. coli and six anaerogenic coli-IThese studies were supported by a grant