Journal Article

PUBDB-2017-08215

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Effect of pH on kinetic parameters of $\mathrm{NAD^+}$-dependent formate dehydrogenase

Mesentsev, A. V. ; Lamzin, V.EMBL* ; Tishkov, V. I. ; Ustinnikova, T. B. ; Popov, V. O.

1997
Portland Pr.8686 London [u.a.]

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Please use a persistent id in citations: doi:10.1042/bj3210475

Abstract: To define in detail the molecular mechanism of NAD+-dependent formate dehydrogenase, the pH dependences of various kinetic and spectroscopic parameters have been studied: Vmax, Km (NAD+), Km (formate), inhibition constants for structural analogues of substrate (NO3-) and product (CNS-, CNO-, N3-), CD and fluorescence properties. The value of Vmax, rate-limiting hydride transfer, is nearly constant throughout the entire pH range of enzyme stability (6.0Ő11.2) but decreases below 6. The Km values for both substrates remain constant within the pH range 6Ő10. At pH values below 6 (for the coenzyme) and above 10 (for both substrate and coenzyme) the Km values increase. In the acidic range this change is attributed to the ionization of two carboxy groups (pK approx. 5.5Ő6.0) located at the NAD+-binding site of the enzyme active centre. The pH transition in the basic region (pK 10.5ŷ0.2) has a conformational origin and affects the enzyme's affinity for substrates and anion inhibitors. A similar transition has been observed for formate dehydrogenases from yeast Candida boidinii and Hansenula polymorpha. The results complement the conclusions about the catalytic mechanism deduced from the crystal structure of the enzyme.

Note: F-Bereich; EMBL

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Contributing Institute(s):

1. DESY Retrocat (DESY(-2012))

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Experiment(s):

1. No specific instrument

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Database coverage:
; BIOSIS Previews ; Current Contents - Life Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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