Pegylated kynureninase enzymes and uses thereof for the treatment of cancer
Kynureninase enzymes covalently bound to polyethylene glycol are described. Aspects of the disclosure provide compositions and methods for improving the effective treatment of cancer by way of kynurenine depletion using such molecules.
1 . A kynureninase homodimer covalently bound to one or more polyethylene glycol (PEG) molecules, wherein the ratio of PEG molecules to homodimer is from 15:1 to 30:1, wherein the homodimer comprises two polypeptide monomers each having an amino acid sequence that is at least 85% identical to the amino acid sequence of SEQ ID NO: 1, wherein each polypeptide monomer comprises the substitutions L72N, H102W, A282P, F306W, S408N, A436T, and N333T relative to SEQ ID NO: 1.
2 . The homodimer of claim 1 , wherein the ratio of PEG molecules to homodimer is from 20:1 to 30:1.
3 . The homodimer of claim 1 , wherein one or more of the PEG molecules each independently has a molecular weight of from about 1 kDa to about 10 kDa.
4 . The homodimer of claim 3 , wherein one or more of the PEG molecules each independently has a molecular weight of about 5 kDa.
5 . The homodimer of claim 1 , wherein the homodimer is covalently bound to the PEG molecule by way of one or more lysine or cysteine residues.
6 . The homodimer of claim 1 , wherein the homodimer comprises two polypeptide monomers each having an amino acid sequence that is at least 85% identical to SEQ ID NO: 3.
7 . The homodimer of claim 1 , wherein the homodimer has a catalytic activity (kcat/KM) of at least 8000M −1 s −1 .
8 . The homodimer of claim 1 , wherein the ratio of PEG molecules to homodimer is about 25:1, one or more of the PEG molecules each independently has a molecular weight of about 5 kDa and is bound to the homodimer by way of an N-hydroxysuccinimide ester carbonate linking group.
9 . A kynureninase homodimer produced by a method comprising contacting the homodimer with a PEGylation agent, wherein the molar input of PEGylation agent to homodimer is from about 15:1 to 30:1, wherein the homodimer comprises two polypeptide monomers each having an amino acid sequence that is at least 85% identical to the amino acid sequence of SEQ ID NO: 1, wherein each polypeptide monomer comprises the substitutions L72N, H102W, A282P, F306W, S408N, A436T, and N333T relative to SEQ ID NO: 1.
10 . A pharmaceutical formulation comprising the kynureninase homodimer of claim 1 in a pharmaceutically acceptable carrier.