title: Hydrolysis and reduction of factor 390 by cell extracts of Methanobacterium thermoautotrophicum (strain delta H).
abstract: Cell extracts of Methanobacterium thermoautotrophicum (strain delta H) were found to perform a hydrogen-dependent reduction of factor 390 (F390), the 8-adenylyl derivative of coenzyme F420. Upon resolution of cell extracts, F390-reducing activity copurified with the coenzyme F420-dependent hydrogenase. This indicates that F390 serves as a substrate of that enzyme. Activity towards F390 was approximately 40-fold lower than that towards coenzyme F420 (0.12 and 5.2 mumol.min-1.mg of protein-1, respectively). In addition, cell extracts catalyzed the hydrolysis of F390 to AMP and coenzyme F420. This hydrolysis required the presence of thiols (6 mM) and much ionic strength (1 M KCl) and was reversibly inhibited by oxygen. The reaction proceeded optimally at pH 8.2 and was Mn dependent. Conditions for F390 hydrolysis in cell extracts are in many respects opposite to those previously described for F390 synthesis.
authors.affiliation: Department of Microbiology, Faculty of Science, University of Nijmegen, The Netherlands.
authors.forename: S W
authors.initials: SW
authors.lastname: Kengen
authors.forename: H W
authors.initials: HW
authors.lastname: von den Hoff
authors.forename: J T
authors.initials: JT
authors.lastname: Keltjens
authors.forename: C
authors.initials: C
authors.lastname: van der Drift
authors.forename: G D
authors.initials: GD
authors.lastname: Vogels
mesh_terms: D000249:Adenosine Monophosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D019605:Euryarchaeota / Q000378:metabolism*; D005415:Flavins; D006868:Hydrolysis; D010084:Oxidation-Reduction; D012256:Riboflavin / Q000031:analogs & derivatives* / Q000378:metabolism; D013057:Spectrum Analysis
chemical_list: D005415:Flavins; C045709:coenzyme F 390 A; D000249:Adenosine Monophosphate; D012256:Riboflavin