Enzyme inhibitors

A compound of formula (I):

• wherein
• A, B and D independently represent ═CH— or ═N—;
• W is —CH═CH— or CH2CH2—;
• R1 is a carboxylic acid group (—COOH), or an ester group which is hydrolysable by one or more intracellular carboxylesterase enzymes to a carboxylic acid group;
• R2 and R3 are selected from the side chains of a natural or non-natural alpha amino acid, provided that neither R2 nor R3 is hydrogen, or R2 and R3, taken together with the carbon to which they are attached, form a 3-6 membered saturated cycloalkyl or heterocyclyl ring;
• Y is a bond, —C(═O)—, —S(═O)2—, —C(C═O)O—, —C(C═O)NR′—, —C(═S)—NR′, —C(═NH)NR′ or —S(═O)2NR′— wherein R′ is hydrogen or optionally substituted C1-C6 alkyl;
• L1 is a divalent radical of formula -(Alk1)m-(Q)n(Alk2)p- wherein
• m, n and p are independently 0 or 1,
• Q is (i) an optionally substituted divalent mono- or bicyclic carbocyclic or heterocyclic radical having 5-13 ring members, or (ii), in the case where both m and p are 0, a divalent radical of formula —X2-Q1- or -Q1-X2— wherein X2 is —O—, —S— or NRA— wherein RA is hydrogen or optionally substituted C1-C3 alkyl, and Q1 is an optionally substituted divalent mono- or bicyclic carbocyclic or heterocyclic radical having 5-13 ring members,
• Alk1 and Alk2 independently represent optionally substituted divalent C3-C7 cycloalkyl radicals, or optionally substituted straight or branched, —C1-C6 alkylene, C2-C6 alkenylene, or C2-C6 alkynylene radicals which may optionally contain or terminate in an ether (—O—), thioether (—S—) or amino (NRA-) link wherein RA is hydrogen or optionally substituted C1-C3 alkyl;
• X1 represents a bond;
• —C(C═O);
• or —S(═O)2—;
• NR4C(═O)—, —C(C═O)NR4—, —NR4C(═O)NR5—, —NR4S(═O)2—, or —S(═O)2NR4— wherein R4 and R5 are independently hydrogen or optionally substituted C1-C6 alkyl;
• and
• z is 0 or 1.