Methyl-coenzyme-M reductase from Methanobacterium thermoautotrophicum (strain Marburg): purity, activity and novel inhibitors
Methyl-coenzyme-M reductase from Methanobacterium thermoautotrophicum (strain Marburg) was purified to a stage where, besides the alpha, beta and gamma subunits, no additional polypeptides were detectable in the preparation. Under appropriate conditions the enzyme was found to catalyze the reduction...
Gespeichert in:
Veröffentlicht in: | European journal of biochemistry 1989-09, Vol.184 (1), p.63-68 |
---|---|
Hauptverfasser: | , , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Methyl-coenzyme-M reductase from Methanobacterium thermoautotrophicum (strain Marburg) was purified to a stage where, besides the alpha, beta and gamma subunits, no additional polypeptides were detectable in the preparation. Under appropriate conditions the enzyme was found to catalyze the reduction of methyl-CoM with 7-mercaptoheptanoylthreonine phosphate (H-S-HTP) to CH4 at a specific rate of 2.5 mumol.min-1.mg protein-1. This finding contradicts a recent report that methyl-CoM reductase is only active when some contaminating proteins are present. The two polypeptides encoded by the open reading frames ORF1 and ORF2 of the methyl-CoM reductase transcription unit did not co-purify with the alpha, beta and gamma subunits. They were neither required nor did they stimulate the activity under the assay conditions. 3-Bromopropanesulfonate (apparent Ki = 0.05 microM) and 2-azidoethanesulfonate (apparent Ki = 1 microM) were found to be two new competitive inhibitors of methyl-CoM reductase. Both inhibitors were considerably more effective than the "classical" 2-bromoethanesulfonate (apparent Ki = 4 microM). |
---|---|
ISSN: | 0014-2956 1432-1033 |
DOI: | 10.1111/j.1432-1033.1989.tb14990.x |