A Capillary Electrophoretic Study on the Specificity of β-Galactosidases fromAspergillus oryzae, Escherichia coli, Streptococcus pneumoniae,andCanavalia ensiformis(Jack Bean)

Solvents derived from glycerol modify classical regioselectivity in the enzymatic synthesis of disaccharides with Biolacta β-galactosidase

“…39,40 This feature is also present in Biolacta crude extract and suggests that both could be indeed the same enzyme. These data also support the idea that protein conglomerates are present in Biolacta preparation and In order to come up with a rational explanation and to confirm our hypothesis about the influence of the solvent properties in reaction stereoselectivity in the glycosidic linkage formation, 30 molecular modeling studies were carried out.…”

“…Also, dielectric constants and dipole moments cover a broad range of values, as well as the Dimroth-Reichardt solvatochromic parameter, E T N . 28 The latter is mainly a measure of the hydrogen- 40 bond donor ability of the solvent, a feature that could also be of importance for solvent-substrate and/or solvent-enzyme interactions. Some of the glycerol-derived solvents used, namely those bearing fluorinated chains, display simultaneously both high hydrophobicity and hydrogen-bond donor ability, a rather 45 unusual combination in conventional organic solvents.…”

“…35 These suggests that these proteins may be assembly in many subunits.(?) ver carta referees First, the regioselectivity showed by this enzyme was 40 investigated when the reaction was carried out in 50 mM citrate/phosphate buffer at pH 5.0 (Table 1). Biolactagalactosidase gave a mixture of regioisomers, the major -(1→4) linker ( 84 % conversion) and minor product -(1→6) linker (17 %).…”

“…The enzyme model revealed that the active center could be similar to E. coli lacZ. A 40 simple superimposition of the structure of a monomer and the model yielded the identification of the catalytic pair (Glu-564 and Glu-645) and the chemical behavior of each of them. Residue Glu-645 corresponds to Glu-537 in lacZ which is accepted as the nucleophile, 41 while Glu-564 was identified as the acid catalyst.…”

“…There are numerous examples in the 35 literature wherein solvents physical properties such as dielectric constant, dipole moment and hydrophobicity are related to various effects on enzyme activity, specificity and enantioselectivity. [6][7][8][9] Nowadays, a new generation of solvents has been developed, 40 whose search has become an area of interest. Currently, water, supercritical fluids (SCFs), fluorous solvents, and solvents from renewable sources are considered green solvents and have been used in biocatalysis.…”