The heme-copper oxidase family consists of three distinct types of terminal oxidases and is related to nitric oxide reductase.

Time-resolved resonance Raman and time-resolved step-scan FTIR studies of nitric oxide reductase from Paracoccus denitrificans: comparison of the heme b3-FeB site to that of the heme-CuB in oxidases.

Time-resolved resonance Raman (TR(3)) and time-resolved step-scan (TRS(2)) FTIR spectroscopies have been used to probe the structural dynamics at the heme b(3) proximal and distal sites after carbon monoxide photolysis from fully reduced CO-bound nitric oxide reductase. The Raman spectra of the transient species exhibit structural differences relative to the equilibrium geometry of heme b(3). T...

Comparison between the nitric oxide reductase family and its aerobic relatives, the cytochrome oxidases.

The denitrification pathway has been studied in the hyperthermophilic archaeon Pyrobaculum aerophilum. In contrast with Gram-negative bacteria, all four denitrification enzymes are membrane-bound. P. aerophilum is also the only denitrifyer identified so far in which menaquinol is the electron donor to all four denitrification reductases. The NO reductase (NOR) of P. aerophilum belongs to the su...

A Theoretical Study of Nitric Oxide Reduction in Heme-Copper Oxidase and Nitric Oxide Reductase

Redox-dependent open and closed forms of the active site of the bacterial respiratory nitric-oxide reductase revealed by cyanide binding studies.

The bacterial respiratory nitric-oxide reductase (NOR) catalyzes the respiratory detoxification of nitric oxide in bacteria and Archaea. It is a member of the well known super-family of heme-copper oxidases but has a [heme Fe-non-heme Fe] active site rather than the [heme Fe-Cu(B)] active site normally associated with oxygen reduction. Paracoccus denitrificans NOR is spectrally characterized by...

Inhibition of chickpea seedling copper amine oxidases by tetraethylenepentamine

Copper amine oxidases are important enzymes, which contribute to the regulation of mono- and polyamine levels. Each monomer contains one Cu(II) ion and 2,4,5-trihydroxyphenylalanine (TPQ) as cofactors. They catalyze the oxidative deamination of primary amines to aldehydes with a ping-pong mechanism consisting of a transamination. The mechanism is followed by the transfer of two electrons to mol...