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Protection of Enzymes during Recycling of Nicotinamide Adenine Dinucleotide (NAD/+/) with Phenazine Methosulphate (PMS) and O(2)

IP.com Disclosure Number: IPCOM000085737D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Slocum, SH: AUTHOR [+2]

Abstract

Several chemical reactions important in industry can be carried out with enzymes as catalysts. Using enzymatic catalysis has the advantage that the reactions are generally free of the side reactions often encountered when the methods of classical organic chemistry are used, and that enzymatic reactions proceed at rapid rates at moderate temperature and pressure.

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Protection of Enzymes during Recycling of Nicotinamide Adenine Dinucleotide (NAD/+/) with Phenazine Methosulphate (PMS) and O(2)

Several chemical reactions important in industry can be carried out with enzymes as catalysts. Using enzymatic catalysis has the advantage that the reactions are generally free of the side reactions often encountered when the methods of classical organic chemistry are used, and that enzymatic reactions proceed at rapid rates at moderate temperature and pressure.

A number of dehydrogenations which might be carried out with enzymes are, on the surface, economically infeasible because an expensive electron acceptor is consumed in the reaction. The enzymes considered here use nicotinamide adenine dinucleotide (NAD/+/) as the electron acceptor in the following reaction:

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substrate + NAD/+/ ----> product + NADH + H/+/.

Regenerating the NAD/+/ with a second, inexpensive electron acceptor provides: EA(2) (oxidized) + NADH + H/+/ --> EA(2) (reduced) + NAD/+/

This allows the spreading the cost of the NAD/+/ over many molecules of product. The net reaction is then: substrate + EA(2) (oxidized) --> product + EA(2) (reduced). and the process may be economically feasible, if the cost of EA(2) is low compared to the value of the product and if the number of NAD/+/ recycles is sufficiently large.

Using molecular oxygen as the second electron acceptor has the advantages that it is inexpensive and that it drives many reactions to completion as a result of its high-redox potential. O(2) does not oxidize NADH directly, but a molecule called phenazine methosulfate (PMS) can be used to pass electrons from NADH to O(2): NADH + H/+/ + PMS (oxidized) --> NAD/+/ + PMS (reduced) PMS (reduced) + O(2) --> PMS (oxidized) + H(2)O NET: NADH + H/+/ + O(2) --> NAD/+/ + H(2)O.

The experiments which have been carried out with the aim of obtaining a high number (>1000) of NAD recycles wit...