N-terminally chemically modified protein compositions and methods

DETAILED DESCRIPTION What is claimed is: 1.
A preparation comprising a predominant amount of a monopolymer/protein conjugate prepared from a hematopoietic protein having one or more available epsilon amino reactive groups, wherein the monopolymer/protein conjugate has a polyethylene glycol polymer moiety located at the N-terminus but not on an epsilon amino group, and the polyethylene glycol polymer moiety is conjugated via an alpha amino group and, wherein the monopolymer/protein conjugate has a prolonged in vivo biological activity relative to the non-conjugated hematopoietic protein.
2.
The preparation of claim 1 wherein the preparation comprises greater than 80% monopolymer/protein conjugate.
3.
The preparation of claim 1 wherein the preparation comprises at least 90% monopolymer/protein conjugate.
4.
The preparation of claim 1 wherein the preparation comprises greater than 95% monopolymer/protein conjugate.
5.
The preparation of claim 1 wherein the preparation comprises at least 99% monopolymer/protein conjugate.
6.
A preparation of a monopegylated hematopoietic protein prepared from a hematopoietic protein having one or more available epsilon amino reactive groups, wherein a polyethylene glycol polymer moiety is conjugated predominantly at the N-terminus of the hematopoietic protein and is conjugated via an alpha amino group and wherein the monopegylated hematopoietic protein has a prolonged in vivo biological activity relative to the non-conjugated hematopoietic protein.
7.
The hematopoietic protein preparation of claim 1 or 6 wherein the polyethylene glycol has a molecular weight of between about 2 kDa and about 100 kDa.
8.
The hematopoietic protein preparation of claim 7 wherein the polyethylene glycol has a molecular weight of about 6 kDa.
9.
The hematopoietic protein preparation of claim 7 wherein the polyethylene glycol has a molecular weight of about 12 kDa.
10.
The hematopoietic protein preparation of claim 7 wherein the polyethylene glycol has a molecular weight of about 20 kDa