Acylases affinities

C. King The Use of Coenzymes in Biochemical Reactors. - C. Wandrey, E Flaschel Process Development and Economical Aspects in Enzyme Engineering Acylase-L-Methionine System. - D.J. Graves, Yun-Tai Wu The Rational Design of Affinity Chromatography Separation Processes. 

As with the D-aminoacylases from Streptomyces sp. the enzymes from Alcaligenes strains have a preference for hydrophobic N-acetyl-amino acids. In this respect, they are similar to the L-specific acylase I from kidney preparations and Aspergillus sp. The Alcaligenesfaecalis enzyme prefers the N-acyl-D-amino acid derivatives from Met, Phe and Leu[951. If a high-affinity substrate residue occupies the hydrophobic side-chain pocket the enzyme even deacylates D-Met methyl esters or N-Ac-D-Met-Xaa dipeptide derivatives. 

Mao QM, Hearn MTW (1996) Optimization of affinity and ion-exchange chromatographic processes for the purification of proteins. Biotechnol Bioeng 52(2) 204-222 Marcos JC, Fonseca LP, Ramalho MT et al. (1999) Partial purification of penicillin acylase from Escherichia coli in poly(ethylene glycol)-sodium citrate aqueous two-phase systems). J Chro-matB 734(1) 15-22... 

The possible existence of multiple ionic forms for the substrate has not been considered, but can also be included (Mesentsev et al. 1997 Pickering et al. 1999). When this is the case, usually only one of those forms is catalytically active as it occurs, for instance, in the synthesis of (3-lactam antibiotics with penicillin acylase, where only the non-ionized form of the nucleophile interacts with the enzyme (Ferreira et al. 2004 Guranda et al. 2004). If binding of the substrate does not affect the ionic equilibria among enzyme species, then pH has no effect on the affinity parameter and Kap = K, as clearly seen from Eq. 3.96. The effect of pH on Kap is usually mild or even negligible (Cornish-Bowden 1976) and, in any case, less important than the effect on Vap- Optimum pH (pH ), regarded as the one that maximizes Vap, can be determined fromEq. 3.93 ... 

Ishii Y, Saito Y, Sasaki H. Uchiyama F, Hayashi M, Nakamura S, Niwa M. Affinity labelling of cephalosporin C acylase from Pseudomonas sp. N176 with a substrate analogue, 7 3-(6 brO (nohexanoylamido)cephalosporanic acid. J Ferment Bioeng 1994 77 598-603. 

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