Inhibition of β-Lactamase II of Bacillus cereus by Penamaldic Derivatives of Penicillins

Abstract

The penamaldic derivatives of amoxicillin, ampicillin, and penicillins G and V, stabilized with Zn 2؉ , were obtained from a methanolic medium. The enzymatic kinetic results show that the these derivatives elicit reversible inhibition of the enzyme metallo-␤-lactamase from Bacillus cereus, with inhibition constant values determined at pH 7.0 and 25°C.Bacteria have developed various strategies to deactivate ␤-lactam antibiotics, including the production of ␤-lactamase enzymes. These have been grouped in four classes (6, 10). Classes A, C, and D contain a catalytic serine residue in their active sites, and several have inhibitors utilized in therapeutics (4,15,16). Class B metalloenzymes require one or two zinc ions to carry out the hydrolysis of the ␤-lactams (3) and act on a wide range of ␤-lactam antibiotics, including carbapenems and inhibitors of the serine-dependent enzymes (12). Over the past 10 years, several inhibitors of these enzymes have been discovered, for instance, two esters of benzyloxycarbonylmethyl-6-aminopenicillanic acid (17), a group of ␣-amido-trifluoromethyl alcohols and ketones (18,19), a series of thiol ester derivatives of mercaptoacetic and mercaptophenylacetic acids (7,8,13,14), and derivatives of ␤-methylcarbapenem (11). More recently, derivatives of cysteinyl peptides have also been tested (1).Because thiol derivatives inhibit the metallo-␤-lactamases (1, 2), the present study tests the enzymatic inhibition of the metallo-␤-lactamase of Bacillus cereus by the Zn 2ϩ -stabilized penamaldic derivatives obtained from ampicillin, amoxicillin, and penicillins G and V. The type of inhibition is determined, and its parameters are calculated.The penamaldic derivatives ( Fig. 1) stabilized with Zn 2ϩ as 2:1 (ligand-metal ion) complexes were obtained by the procedure described in a previous paper (9). The results of the chemical analysis of the polycrystalline solids obtained and the infrared and 1 H-nuclear magnetic resonance data were compatible with the formation of such complexes. According to the thermogravimetric analysis data, the structures of all solids feature two water molecules of crystallization, and the derivatives of ampicillin and amoxicillin have a molecule of NaCl.The spectra of the penamaldic derivatives in the 50 mM MOPS (morpholinepropanesulfonic acid) medium, at pH 7 and 25°C, scarcely varied over time. Generally, the degradation of the four penamaldic derivatives produced an insignificant change in the rate of absorbance over time compared with that for the degradation of substrate in the enzymatic reaction. This may be attributed to the fact that Zn 2ϩ -stabilized penamaldic derivative compounds have a high constant of formation in an aqueous medium. Moreover, the slight instability of the Zn 2ϩ -stabilized compounds in aqueous solution, presumably because of the enamine moiety, can tautomerize to imines, which undergo ester hydrolysis (5). In the presence of enzymes the spectra of the penamaldic derivatives showed the same changes over time as those observed for the der...

Metallo-?-lactamases: two binding sites for one catalytic metal ion?

“…They belong to different substance classes, namely tricyclic natural products from Chaetomium funicola [115], trifluoromethyl alcohols and ketones [116], hydroxamic acids [117], mercaptocarboxylates [51, 118 -120], biphenyl tetrazoles [46], carbapenem derivatives [121,122], cephamycins and moxalactam [123], thiols [40,119,120,124,125], cysteinyl peptides [125], inhibitors derived from single-domain antibody fragments elicited in the Camelidae [126], thioesters [34,119,124] phenazines from a Streptomyces [127], 2,3-disubstituted succinic acid [128], sulphonylhydrazones [129], disulphides [130], tioxo-cephalosporin derivatives [131] and penamaldic derivatives of penicillins [131,132]. In particular, the substituted succinic acids [128] and mercapto-carboxylic inhibitors [118,119] are potent inhibitors with inhibition constants in the nanomolar range.…”

Penicillin G's function, metabolites, allergy, and resistance.

“…It is worth noting that penicillin reacts rapidly with cystine residues, approximately 10 4 times faster than with alanine residues [78]. It is quite possible that the free thiol groups within isopenillic acid and other penamaldic derivatives could react with cystine residues as well ( Figure 5A and 5B) [79]. Furthermore, disulfide metabolite-metabolite interactions occur, such as penicillenic acid disulfide, and could be the cause of an immune response ( Figure 5C) [35].…”

Medium Optimization for Penicillin Acylase (PAc) Production by Recombinant B. megaterium MS941 Containing pac Gene from B. thuringiensis BGSC BD1 Using Response Surface Methodology

“…Komposisi media optimal diaplikasikan -1 pada skala bioreaktor 10 L, aktivitas tertinggi (2,0687 ± 0,0820 unit mL ) dan kadar protein tertinggi (0,0078 ± (Madigan et al 2003). Overuse of pen-G led to a bacterial pathogen resistance due to the production of β-lactamase which hydrolyzes β-lactam ring of penicillin rendering it inactive (Navarro et al 2004). Pen-G's sensitivity to β-lactamase, its limited activity to gram positive bacteria and possibility to cause allergy raised problems of using this antibiotic (Madigan et al 2005).…”