Enzyme design criterion

The self-phosphorylation process catalyzed by many protein kinases as part of the regulatory mechanism for their own activation. Because true autophosphorylation is a unimolecular reaction involving enzyme both as catalyst and phosphoryl acceptor, the fraction of autophosphory-lated enzyme at any time after addition of ATP (or another phosphoryl donor) will be independent of the initial concentration of the enzyme. This criterion was first applied to the autophosphorylation of cardiac muscle cyclic AMP-stimulated protein kinase, now designated protein kinase A (PKA). At a fixed concentration of MgATP , the fraction of autophosphorylated protein will follow the first-order rate laws, [A]/[A ] where k is a first-order rate constant. 

With immobilized enzymes in a fixed-bed reactor, a constant residence time T in the fixed bed is the applicable design criterion for scale-up. 

Fluidity can be assumed to stay constant when scaling up an enzyme-substrate system, provided that solutions of identical composition are used for the laboratory-scale model and the full-size plant design. Application of the design criterion in Eq. (19.36) assumes operation in the linear regime of transmembrane pressure AP up to about 1-2 bar, as described in Chapter, Section 8.5.1, Eq. (8.78), so that... 

Aside from the criterion stated initially, there are several other factors which must be considered in the design and development of enzyme electrodes, or biochemical-specific electrodes as Gough and Andrade (1973) have defined them. 

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