Affordable Access

Publisher Website

Identification and characterization of theTuber borchiid-mannitol dehydrogenase which defines a new subfamily within the polyol-specific medium chain dehydrogenases

Authors
Journal
Fungal Genetics and Biology
1087-1845
Publisher
Elsevier
Publication Date
Volume
44
Issue
10
Identifiers
DOI: 10.1016/j.fgb.2007.01.002
Keywords
  • D-Mannitol
  • D-Mannitol Dehydrogenase
  • Mdr Superfamily
  • Symbiotic Fungus
  • Tuber Borchii
Disciplines
  • Biology

Abstract

Abstract A novel NADP +-dependent d-mannitol dehydrogenase and the corresponding gene from the plant symbiotic ascomycete fungus Tuber borchii was identified and characterized. The enzyme, called TbMDH, is a homotetramer with two zinc atoms per subunit. It catalyzed both d-fructose reduction and d-mannitol oxidation, although it showed the highest substrate specificity and catalytic efficiency for d-fructose. Co-factor specificity was restricted to NADP(H) and the reaction proceeded via a sequential ordered Bi Bi mechanism. The carbon responsive transcriptional pattern showed that Tbmdh is up-regulated when mycelia are transferred to a culture medium containing d-mannitol or d-fructose. The phylogenetic analysis showed TbMDH to be the first example of a fungal d-mannitol-2-dehydrogenase belonging to the medium-chain dehydrogenase/reductases (MDRs). The enzyme identified a new group of proteins, most of them annotated in databases as hypothetical zinc-dependent dehydrogenases, forming a distinct subfamily among the polyol dehydrogenase family.

There are no comments yet on this publication. Be the first to share your thoughts.