Substrate Conformation Correlates with the Outcome of Hyoscyamine 6β-Hydroxylase Catalyzed Oxidation Reactions

Tetrahydropterin oxidation without hydroxylation catalyzed by rat liver phenylalanine hydroxylase.

Mechanism of oxidation reactions catalyzed by cytochrome p450 enzymes.

ion phase that leads to an alkyl radical coordinated to the iron-hydroxo complex by a weak OH---C hydrogen bond, labeled as CI; (ii) an alkyl (or OH) rotation phase whereby the alkyl group achieves a favorable orientation for rebound; and (iii) a rebound phase that leads to C-O bond making and the ferric-alcohol complexes, 4,2P. The two profiles remain close in energy throughout the first two p...

H2 oxidation versus organic substrate oxidation in non-heme iron mediated reactions with H2O2.

Herein we show that species generated upon reaction of α-[Fe(CF3SO3)2(BPMCN)] (BPMCN = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane) with H2O2 (putatively [Fe(V)(O)(OH)(BPMCN)]) is able to efficiently oxidize H2 to H2O even in the presence of organic substrates, while species formed in the presence of acetic acid (putatively [Fe(V)(O)(OAc)(BPMCN)]) prefer organic substrate oxidation o...

Conformation of the substrate and pterin cofactor bound to human tryptophan hydroxylase. Important role of Phe313 in substrate specificity.

Tryptophan hydroxylase (TPH) carries out the 5-hydroxylation of L-Trp, which is the rate-limiting step in the synthesis of serotonin. We have prepared and characterized a stable N-terminally truncated form of human TPH that includes the catalytic domain (Delta90TPH). We have also determined the conformation and distances to the catalytic non-heme iron of both L-Trp and the tetrahydrobiopterin c...

Substrate inhibition kinetics for cytochrome P450-catalyzed reactions.

Most cytochrome P450 (P450 or CYP)-catalyzed reactions are adequately described by classical Michaelis-Menten kinetic parameters (e.g., Km and Vmax), which are usually determined by a saturation profile of velocity of product formation versus substrate concentration. In turn, these parameters may be used to predict pharmacokinetics. However, some P450 enzymes exhibit atypical or non-Michaelis-M...