Partenaires

CNRS


Rechercher


Accueil > Publications > Recherche par années > Années 1990 > 1993

Marvinsikkema, FD ; Gomes, TMP ; Grivet, JP ; Gottschal, JC ; Prins, RA

Characterization of hydrogenosomes and their role in glucose-metabolism of neocallimastix sp l2

Archives of Microbiology 160 (5) 388-396

par Administrateur - publié le

Abstract :

In the anaerobic fungus Neocallimastix. sp. L2 fermentation of glucose proceeds via the Embden-Meyerhof-Parnas pathway. Enzyme activities leading to the formation of succinate, lactate, ethanol, and formate are associated with the cytoplasmic fraction. The enzymes ’malic enzyme’, NAD(P)H:ferredoxin oxidoreductase ; pyruvate : ferredoxin oxidoreductase, hydrogenase, acetate : succinate CoA transferase and succinate thiokinase leading to the formation of H-2, CO2, acetate, and ATP are localized in microbodies. Thus, these organelles are identified as hydrogenosomes. In addition, the microbodies contain the O2-scavenging enzymes NADH- and NADPH oxidase, while NAD(P)H peroxidase, catalase, or superoxide dismutase could not be detected. In cell-free extracts from zoospores of Neocallimastix sp. L2 the specific activities of hydrogenosomal enzymes as well as the quantities of these proteins are 2- to 6-fold higher than in mycelium extracts. These findings suggest that hydrogenosomes perform an important role - especially in zoospores - as H-2-evolving, ATP-generating and O2-scavenging organelles.