Metabolic enzymes from psychrophilic bacteria: challenge of adaptation to low temperatures in ornithine carbamoyltransferase from Moritella abyssi.

ABSTRACT: The enzyme ornithine carbamoyltransferase (OTCase) of Moritella abyssi (OTCase(Mab)), a new, strictly psychrophilic and piezophilic bacterial species, was purified. OTCase(Mab) displays maximal activity at rather low temperatures (23 to 25 degrees C) compared to other cold-active enzymes and is much less thermoresistant than its homologues from Escherichia coli or thermophilic procaryotes. In vitro the enzyme is in equilibrium between a trimeric state and a dodecameric, more stable state. The melting point and denaturation enthalpy changes for the two forms are considerably lower than the corresponding values for the dodecameric Pyrococcus furiosus OTCase and for a thermolabile trimeric mutant thereof. OTCase(Mab) displays higher K(m) values for ornithine and carbamoyl phosphate than mesop

SUBMITTER: Xu Y 

PROVIDER: S-EPMC151491 | biostudies-literature | 2003 Apr

REPOSITORIES: biostudies-literature