Novel enzyme derivatives

Claim 2

A derivative of a fibrinolytic enzyme in which the catalytic site on the enzyme which is responsible for fibrinolytic activity is blocked by a human protein attached thereto by way of a reversible linking group.

Claim 3

A derivative according to claim 1 in which the catalytic site on the enzyme is blocked by a group of formula (I): P--B--A--X (I) in which P is a human protein modified by treatment with an amino acid side chain specific reagent to include a protein attachment group; X is an acyl group of formula ##STR4## wherein R is an aliphatic or aromatic residue, A is a bridging group comprising at least one heteroatom selected from oxygen sulphur and nitrogen, in which the nitrogen is optionally substituted by alkyl of 1 to 6 carbon atoms, and B is a hydrophilic linking group, linked to the protein attachment group on P.

Claim 4

A derivative according to claim 2 wherein group B is a --S--(CH 2 ) 2 CONH--, --S--(CH 2 ) 2 CONH(CH 2 ) 6 -- or --S--(CH 2 ) 2 CONH(CH 2 ) 2 --.

Claim 5

A derivative according to claim 1 wherein the fibrinolytic enzyme is tissue type plasminogen activator, urokinase or plasmin.

Claim 6

A derivative according to claim 1 wherein the human protein is human serum albumin, immunoglobulin, human fibrinogen, human plasminogen or a fibrinolytic enzyme or proenzyme thereof.

Claim 7

A derivative according to claim 1 which is human serum albumin→human tissue plasminogen activator human serum albumin→urokinase urokinase or acylated urokinase→human plasmin human tissue plasminogen activator→human plasmin human immunoglobulin G→human tissue plasminogen activator human plasminogen→human tissue plasminogen activator where→represents a reversible linkage to the active centre of the enzyme.

Claim 8

A process for preparing a derivative according to claim 1 which process comprises reacting together a human protein optionally modified to include a protein attachment group, a fibrinolytic enzyme and a linking agent having a moiety capable of reacting with the catalytic site of the enzyme and a moiety capable of reacting with a protein amino group or protein attachment group to form a reversible linking group.

Claim 9

A pharmaceutical composition useful for treating thrombotic diseases in humans which comprises a therapeutically effective amount of a derivative of a fibrinolytic enzyme in which the catalytic site on the enzyme which is responsible for fibrinolytic activity is blocked by a human protein attached thereto by way of a reversible linking group, in combination with a pharmaceutically acceptable carrier.

Claim 10

A pharmaceutical composition useful for treating thrombotic diseases in humans which comprises a therapeutically effective amount of a derivative of a fibrinolytic enzyme in which the catalytic site on the enzyme which is responsible for fibrinolytic activity is blocked by a human protein attached thereto by way of a reversible linking group, in combination with a pharmaceutically acceptable carrier.

Claim 11

A composition according to claim 8 in which the catalytic site on the enzyme is blocked by a group of Formula (I): P--B--A--X (I) in which P is a human protein modified by treatment with an amino acid side chain specific reagent to include a protein attachment group; X is an acyl group of the Formula: ##STR5## wherein R is an aliphatic or aromatic residue; A is a bridging group comprising at least one heteroatom selected from oxygen, sulphur and nitrogen, in which the nitrogen is optionally substitued by alkyl of 1 to 6 carbon atoms; and B is a hydrophilic linking group, linked to the protein attachment group on P.

Claim 12

A composition according to claim 9 wherein group B is a --S--(CH 2 ) 2 CONH--, --S--(CH 2 ) 2 CONH(CH 2 ) 6 -- or --S--(CH 2 ) 2 COHN(CH 2 ) 2 --.

Claim 13

A compostion according to claim 8 wherein the fibrinolytic enzyme is tissue type plasminogen activator, urokinase or plasmin.

Claim 14

A composition according to claim 8 wherein the human protein is human serum albumin, immunoglobulin, human fibrinogen, human plasminogen or a fibrinolytic enzyme or proenzyme thereof.

Claim 15

A composition according to claim 8 wherein the derivative is: human serum albumin→human tissue plasminogen activator; human serum albumin→urokinase; urokinase or acylated urokinase→human plasmin; human tissue plasminogen activator→human plasmin; human immunoglobulin G→human tissue plasminogen activator; human plasminogen→human tissue plasminogen activator; where → represents a reversible linkage to the active center of the enzyme.

Claim 16

A composition according to claim 8 in intravenous administration form.

Claim 19

A method according to claim 15 in which the catalytic site on the enzyme is blocked by a group of Formula (I): P--B--A--X (I) in which P is a human protein modified by treatment with an amino acid side chain specific reagent to include a protein attachment group; X is an acyl group of the Formula: ##STR6## wherein R is an aliphatic or aromatic residue; A is a bridging group comprising at least one heteroatom selected from oxygen, sulphur and nitrogen, in which the nitrogen is optionally substituted by alkyl of 1 to 6 carbon atoms; and B is a hydrophilic linking group, linked to the protein attachment group on P.

Claim 20

A method according to claim 16 wherein group B is a --S--(CH 2 ) 2 CONH--, --S--(CH 2 ) 2 CONH(CH 2 ) 6 -- or --S--(CH 2 ) 2 COHN(CH 2 ) 2 --.

Claim 21

A method according to claim 15 wherein the fibrinolytic enzyme is tissue type plasminogen activator, urokinase or plasmin.

Claim 22

A method according to claim 15 wherein the human protein is human serum albumin, immunoglobulin, human fibrinogen, human plasminogen or a fibrinolytic enzyme or proenzyme thereof.

Claim 23

A method according to claim 15 wherein the derivative is: human serum albumin→human tissue plasminogen activator; human serum albumin→urokinase; urokinase or acylated urokinase→human plasmin; human tissue plasminogen activator→human plasmin; human immunoglobulin G→human tissue plasminogen activator; human plasminogen→human tissue plasminogen activator; where → represents a reversible linkage to the active center of the enzyme.

Claim 24

A method according to claim 15 wherein the administration is intravenous.