Stabilizing effect of penicillin G sulfoxide, a competitive inhibitor of penicillin G acylase: its practical applications.
We have found that penicillin G sulfoxide (pen G SO) behaves as a general stabilizing agent of two bacterial penicillin G acylases (PGAs) from E. coli and from K. citrophila), and this role is related to a strong inhibitory effect on the enzymes. The stabilizing effect has been observed during two different inactivation processes: (i) thermal inactivation of soluble enzymes at alkaline pH, and (ii) inactivation of immobilized enzymes as a consequence of covalent multiinteraction with highly activated agarose aldehyde gels. At the same time, pen G SO behaves as a strong competitive inhibitor of these two enzymes. The inhibition constant is more than 10-fold lower than the one corresponding to another smaller competitive inhibitor, phenylacetic acid (PAA), the structure of which is exactly the acyl donor moiety corresponding to pen G SO. In turn, PAA hardly exerts any stabilizing effect on PGAs. The stabilizing effect of pen G SO allowed the preparation of derivatives of these PGAs preserving full catalytic activity in spite of being 1,400- and 650-fold more stable than the corresponding soluble or one-point attached immobilized enzymes.
Alvaro
G
G
Instituto de Catálisis, C.S.I.C. Serrano, Madrid, Spain.
Fernandez-Lafuente
R
R
Blanco
R M
RM
Guisán
J M
JM
D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000037:antagonists & inhibitors*; D004926:Escherichia coli / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007716:Kluyveromyces / Q000201:enzymology; D010399:Penicillin Amidase / Q000037:antagonists & inhibitors*; D010400:Penicillin G / Q000031:analogs & derivatives* / Q000494:pharmacology; D013816:Thermodynamics
D004800:Enzymes, Immobilized; C059126:penicillin G sulfoxide; D010399:Penicillin Amidase; D010400:Penicillin G