TABLE 5.

Characteristics of experimental MBL inhibitors

Inhibitor type	Representative compound	Enzyme tested	Affinitya (μM)	Demonstrable potentiation	Reference
Thioester derivative	Morpholinoethanesulfonic acid	CcrA	Ki 23	NDb	44
	SB217782/8018/9158	L1	IC50 <1.9	ND	119
	SB214752	L1	IC50 2	ND	119
	Biphenylmethyl derivatives	IMP-1	IC50 0.0004	Potentiation with E. coli expressing IMP-1	170
		CcrA	IC50 180	ND
Trifluoromethyl alcohol	d-Alanine derivative	L1	Ki 1.5	ND	182
		BCII	Ki 300	ND
Thiol	Mercaptoacetic acid	IMP-1	Ki 0.23	ND	56
	Mercaptopropionic acid	IMP-1	Ki 0.19	ND
	2′-Mercaptoethyl-derivative	BCII	Ki 70	ND	18
	Thiobenzoate derivative	IMP-1	IC50 0.0004	ND	57
		CcrA	IC50 180	ND
	2-para-Thiomandelic acid	BCII	Ki 0.21	ND	101
	Quinoline C45H	IMP-1	IC50 1.2	ND	71
		VIM-2	IC50 1.1	ND
Sulfonyl hydrazone	2-Naphthyl derivatives	IMP	IC50 1.6	ND	160
Tricyclic product	SB238569	BCII	Ki 79	ND	122
		IMP-1	Ki 17	No potentiation found with P. aeruginosa (IMP-1)
		CcrA	Ki 3.4	8-fold synergistic effect with B. fragilis (CcrA)
	2S-3S disubstitute	IMP-1	IC50 >0.21	ND	171
Biphenyl tetrazole	L161, 189	CcrA	IC50 0.30	Possessed activity alone and potentiation with imipenem against B. fragilis (CcrA)	170
Cysteinyl peptide	d-Phenylalanine derivative	BCII	Ki 3.0	ND	17
1-β-Methyl-carbapenem	J-110, 441	IMP-1	Ki 0.0037	Potentiation with imipenem for S. marcescens (IMP-1) and for some P. aeruginosa (IMP-1) strains	104
		CcrA	Ki 0.23	ND
		L1	Ki 1.0	ND
		BCII	Ki 0.83	ND
	J111, 225	IMP-1	Ki 0.18	8-fold potentiation with imipenem for P. aeruginosa (IMP-1)	105
Penicillin derivative	Penicillinate sulfone	L1	IC50 0.10	Some potentiation evident with piperacillin/tazobactam against E. coli (IMP-1)	25
		BCII	IC50 1.4	See above
Thioxocephalosporin	Thioacid	BCII	Ki 96	ND	173

^aIC₅₀, concentration of inhibitor required to inhibit 50% of MBL activity.

^bND, no data.