Enzyme assays

Claim 1

An enzyme substrate of formula S'--X--A--Y--NO 2 , wherein A represents an aromatic nucleus, X represents an auxochromic radical, Y represents an unsaturated group which is capable of transmitting electron resonance between the aromatic nucleus A and the nitro (NO 2 ) substituent, and S' is selected from the group consisting of propionyloxy, palmitoyloxy, phosphate, diphosphate, sulfate, and glycosyl residue.

Claim 13

A method for the assay of an enzyme which comprises: incubating a sample containing said enzyme with a reagent comprising a substrate for said enzyme which reacts with said enzyme to give rise to the formation of a compound which is monitored, wherein said substrate has the formula S'--X--A--Y--NO 2 , and said monitored compound has the formula HX--A--Y--NO 2 , wherein S' comprises the enzyme substrate portion of the reagent, A represents an aromatic nucleus, HX represents an auxochromic group and Y represents an unsaturated group which is capable of transmitting electron resonance between the aromatic nucleus (A) and the nitro substituent (NO 2 ), said monitored compound being capable of producing a visual signal which is discernable by eye either directly or on alkaline treatment.

Claim 14

A method for the assay of an enzyme which comprises: incubating a sample containing said enzyme with a reagent comprising a substrate for said enzyme which reacts with said enzyme to give rise to the formation of a compound which is monitored, wherein said substrate has the formula S'--X--A--Y--NO 2 , and said monitored compound has the formula HX--A--Y--NO 2 , wherein S' comprises the enzyme substrate portion of the reagent, A represents an aromatic nucleus, HX represents an auxochromic group and Y represents an unsaturated group which is capable of transmitting electron resonance between the aromatic nucleus (A) and the nitro substituent (NO 2 ), said monitored compound being capable of producing a visual signal which is discernable by eye either directly or on alkaline treatment.

Claim 16

A method according to claims 11 or 12 wherein said monitored compound has formula I ##STR8## wherein HX is an auxochromic group; n is 1, 2 or 3; R 1 , R 2 , R 3 and R 4 are the same or different and selected from the group consisting of H, Me, NO 2 , CH 3 , CH═CR'R", and CO 2 H; wherein R' and R" are the same or different and selected from the group consisting of H, Me, NO 2 , CH 3 , CO 2 H, and further conjugated unsaturated substituent of formula CH═CR'R".

Claim 17

A method according to claims 11 or 12 in which sample and reagent are incubated together at a temperature greater than 30° C. for a period of up to 30 minutes.

Claim 18

A method according to claims 11 or 12, in which the reagent is used in association with an insoluble solid phase material.

Claim 19

A method according to claims 11 or 12, wherein a solution containing the compound of formula HX--A--Y--NO 2 is brought into contact with a solid phase reagent which presents an alkaline environment to said compound.

Claim 20

An apparatus for the assay of an enzyme in the form of a flow-through device which comprises: an incubation compartment; a visualization compartment; an outlet in said incubation compartment interconnectable to an inlet in said visualization compartment; said incubation compartment containing a reagent comprising a substrate for said enzyme which reacts with said enzyme to give rise to the formation of a compound which is monitored, wherein said substrate has the formula S'--X--A--Y--NO 2 , and said monitored compound has the formula HX--A--U--NO 2 , wherein S' represents the enzyme substrate portion of the reagent, A represents an aromatic nucleus, X represents an auxochromic group, and Y represents an unsaturated group which is capable of transmitting electron resonance between the aromatic nucleus (A) and the nitro substituent (NO 2 ), said monitored compound being capable of producing a visual signal which is discernable by eye directly or on alkaline treatment; said visualization compartment containing a solid phase reagent which presents an alkaline environment to said monitored compound of formula HX--A--Y--NO 2 .

Claim 21

An apparatus for the assay of an enzyme in the form of a flow-through device which comprises: an incubation compartment; a visualization compartment; an outlet in said incubation compartment interconnectable to an inlet in said visualization compartment; said incubation compartment containing a reagent comprising a substrate for said enzyme which reacts with said enzyme to give rise to the formation of a compound which is monitored, wherein said substrate has the formula S'--X--A--Y--NO 2 , and said monitored compound has the formula HX--A--U--NO 2 , wherein S' represents the enzyme substrate portion of the reagent, A represents an aromatic nucleus, X represents an auxochromic group, and Y represents an unsaturated group which is capable of transmitting electron resonance between the aromatic nucleus (A) and the nitro substituent (NO 2 ), said monitored compound being capable of producing a visual signal which is discernable by eye directly or on alkaline treatment; said visualization compartment containing a solid phase reagent which presents an alkaline environment to said monitored compound of formula HX--A--Y--NO 2 .

Claim 24

The apparatus of any of claims 17, 18 or 19 wherein said substrate for said enzyme has the formula S'X--A--Y--NO 2 ; wherein X represents an auxochromic radical corresponding to said auxochromic group XH, and S is selected from the group consisting of propionyloxy, palmitoyloxy, phosphate, diphosphate, sulfate and glycosyl residue.

Claim 26

The apparatus of claims 17, 18 or 19 wherein said substrate of said enzyme in said incubation compartment is in combination with a solid phase material.