G-CSF conjugates
Polypeptide conjugates with G-CSF activity comprising a polypeptide having at least one introduced lysine residue and at least one removed lysine residue compared to the sequence of human G-CSF, and which are conjugated to 2-6 polyethylene glycol moieties. The conjugates have a low in vitro bioactivity, a long in vivo half-life, a reduced receptor-mediated clearance, and provide a more rapid stimulation of production of white blood cells and neutrophils than non-conjugated recombinant human G-CSF.
1. A polypeptide conjugate exhibiting G-CSF cell proliferation activity, wherein the conjugate comprises
a) a polypeptide comprising an amino acid sequence consisting of SEQ ID NO:1 with the substitutions K16R, K34R, K40R, T105K, and S159K, and
b) at least two polyethylene glycol moieties each covalently attached to an attachment group of the polypeptide,
wherein the attachment group is the N-terminal amino group or a lysine residue.
2. A composition comprising
(a) a polypeptide conjugate exhibiting G-CSF cell proliferation activity, wherein the conjugate comprises
(i) a polypeptide comprising an amino acid sequence consisting of SEQ ID NO:1 with the substitutions K16R, K34R, K40R, T105K and S159K, and
(ii) at least two polyethylene glycol moieties each covalently attached to an attachment group of the polypeptide, wherein the attachment group is the N-terminal amino group or a lysine residue; and
(b) a pharmaceutically acceptable carrier or excipient.
3. The polypeptide conjugate of claim 1 , wherein the polypeptide further comprises a methionine at the N-terminus.
4. The composition of claim 2 , wherein the polypeptide further comprises a methionine at the N-terminus.
5. The polypeptide conjugate of claim 1 , wherein the polyethylene glycol moieties each have a molecular weight of about 5 kilodaltons.
6. The polypeptide conjugate of claim 1 , comprising 3-6 polyethylene glycol moieties.
7. The polypeptide conjugate of claim 6 , wherein the polyethylene glycol moieties are attached to the N-terminal amino group and to one or more lysine residues.
8. The polypeptide conjugate of claim 7 , wherein the one or more lysine residues are selected from Lys23, Lys105, and Lys159.
9. The polypeptide conjugate of claim 8 , wherein the polyethylene glycol moieties each have a molecular weight of about 5 kilodaltons.
10. The composition of claim 2 , wherein the polyethylene glycol moieties each have a molecular weight of about 5 kilodaltons.
11. The composition of claim 2 , comprising 3-6 polyethylene glycol moieties.
12. The composition of claim 11 , wherein the polyethylene glycol moieties are attached to the N-terminal amino group and to one or more lysine residues.
13. The composition of claim 12 , wherein the one or more lysine residues are selected from Lys23, Lys105, and Lys159.
14. The composition of claim 13 , wherein the polyethylene glycol moieties each have a molecular weight of about 5 kilodaltons.