title: Effects of carrier morphology and buffer diffusion on the expression of enzymatic activity.
abstract: A very stable esterase (EC 3.1.1.-), which hydrolyses ethyl acetate, cephalosporin C and other acetyl esters with a maximum turnover number of 3-10(2) s-1, was isolated from Bacillus subtilis ATCC 6633 and immobilized on two supports: controlled-pore glass and powdered brick, a representative of carriers having a wide pore-size distribution. Carrier morphology determines diffusion rates and the expression of activity. Rate-limiting mass transfer of buffer leads to apparent losses of activity, gross distortions of molecular pH vs. activity profiles and to apparent deviations from Michaelis-Menten kinetics.
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology; D002021:Buffers; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005898:Glass; D007700:Kinetics; D008628:Mercury; D008970:Molecular Weight; D013379:Substrate Specificity
chemical_list: D002021:Buffers; D004800:Enzymes, Immobilized; D002265:Carboxylic Ester Hydrolases; D008628:Mercury