|Title:||N-terminally chemically modified protein compositions and methods|
|Abstract:||Provided herein are methods and compositions relating to the attachment of water soluble polymers to proteins. Provided are novel methods for N-terminally modifying proteins or analogs thereof, and resultant compositions, including novel chemically modified G-CSF compositions and related methods of preparation. Also provided is chemically modified consensus interferon.|
|Inventor(s):||Kinstler; Olaf B. (Thousand Oaks, CA), Gabriel; Nancy E. (Newbury Park, CA), Farrar; Christine E. (Newbury Park, CA), DePrince; Randolph B. (Raleigh, NC)|
|Assignee:||Amgen Inc. (Thousand Oaks, CA)|
|Filing Date:||Jun 20, 1997|
|Claims:||1. A substantially homogenous preparation of N-terminally PEGylated consensus interferon, said preparation being essentially free of consensus interferon PEGylated at sites other than the N-terminus. |
2. A method for attaching a polyethylene glycol molecule to a consensus interferon molecule, wherein said polyethylene glycol molecule has a single reactive aldehyde group, said method comprising:
(a) reacting said consensus interferon with said polyethylene glycol molecule under reducing alkylation conditions, at a pH sufficiently acidic to selectively activate the .alpha.-amino group at the amino terminus of said consensus interferon; and
(b) obtaining the pegylated consensus interferon and
(c) optionally, separating the pegylated consensus interferon from non-pegylated consensus interferon.
3. A method of claim 2 wherein said polyethylene glycol molecule has a molecular weight of about 2 kDa to about 100 kDa.
4. The pegylated consensus interferon product produced by the process of claim 2.
5. A preparation of claim 1 comprising about 90% monoPEGylated consensus interferon and about 10% unPEGylated consensus interferon.
6. A pharmaceutical composition comprising: (a) a substantially homogenous preparation of monoPEGylated consensus interferon, said monoPEGylated consensus interferon consisting of a polyethylene glycol moiety connected to a consensus interferon moiety solely at the N-terminus thereof via an amine linkage; (b) fewer than 5% nonPEGylated consensus interferon molecules; and (c) a pharmaceutically acceptable diluent, adjuvant or carrier.