What is TON and TOF?

TON and TOF are terms used in catalysis, respectively “Turn Over Number” and “Turn Over Frequency”. They indicate the maximum number of conversions per unit of catalyst (with a cut-off value) and the turnover frequency per unit of catalyst.

How do you calculate turnover frequency?

Turnover number (TON) = number of moles of reactant consumed/(mole of catalyst). Turnover frequency (TOF) = TON/time of reaction.

How do you calculate tons of enzymes?

TOF = Moles of desired product formed/moles of catalyst/ time = TON/time. it just give the number of molecules reacted per active sites of catalyst. When you take TON at different time the quantity will be different.

How do you calculate carbonic anhydrase turnover number?

In enzymology, turnover number (also termed kcat) is defined as the maximum number of molecules of substrate that an enzyme can convert to product per catalytic site per unit time and can be calculated as follows: kcat = Vmax/[E]T (see Michaelis-Menten kinetics).

What is turnover frequency TOF?

“The turnover frequency (TOF) is a measure of the instantaneous efficiency of a catalyst, calculated as the derivative of the number of turnovers of the catalytic cycle with respect of the time per active site, at such a low concentration of the catalyst that exhibits infinite dilution behavior and the reactants and …

What is a TOF number?

The term turnover frequency (abbreviated TOF) is used to refer to the turnover per unit time, equivalent to the meaning of turnover number in enzymology. For most relevant industrial applications, the turnover frequency is in the range of 10−2 – 102 s−1 (103 – 107 s−1 for enzymes).

What is meant by turnover number?

Turnover number is defined as the number of substrate molecules transformed per minute by a single enzyme molecule when the enzyme is the rate-limiting factor. From: Microsomes, Drug Oxidations and Chemical Carcinogenesis, Volume 1, 1980.

What is ton in catalysis?

“Turnover number (TON) specifies the maximum use that can be made of a catalyst for a special reaction under defined reaction conditions by the number of molecular reactions or reaction cycles occurring at the reactive center up to the decay of activity.

How is k2 the turnover number of an enzyme calculated?

c – divide Vmax by the total enzyme concentration. Vmax = k2 [E]total, k2 = Vmax/ [E]total.

What is turnover number and why is it important?

Turnover number defines the rate at which an enzyme converts its substrate, usually in terms of the number of substrate molecules that can be converted by a single enzyme molecule and can range from a few molecules to several million molecules per second [1].

Is turnover number constant?

The turnover number per mole of enzyme is a zeroorder rate constant because it does not depend on the substrate concentration. Some enzymes, such as hexokinase (EC 2.7. 1.1), catalyze the conversion of several different substrates to different products.