GLYCOPEGYLATED FOLLICLE STIMULATING HORMONE
The invention provides conjugates between follicle stimulating hormone and PEG moieties. The conjugates are linked via an intact glycosyl linking group that is interposed between and covalently attached to the peptide and the modifying group. The conjugates are formed from both glycosylated and unglycosylated peptides by the action of a glycosyltransferase. The glycosyltransferase ligates a modified sugar moiety onto either an amino acid or glycosyl residue on the peptide. Also provided are pharmaceutical formulations including the conjugates. Methods for preparing the conjugates are also within the scope of the invention.
1 . A method of making a FSH peptide conjugate comprising the moiety:
wherein
D is a member selected from —OH and R 1 -L-HN—;
G is a member selected from R 1 -L- and —C(O)(C 1 -C 6 )alkyl;
R 1 is a moiety comprising a member selected a straight-chain or branched poly(ethylene glycol) residue; and
L is a linker which is a member selected from a bond, substituted or unsubstituted alkyl and substituted or unsubstituted heteroalkyl,
such that when D is OH, G is R 1 -L-, and when G is —C(O)(C 1 -C 6 )alkyl, D is R 1 -L-NH—,
said method comprising:
(a) contacting a substrate FSH peptide with a PEG-sialic acid donor moiety having the formula:
and an enzyme that transfers said PEG-sialic acid onto an amino acid or glycosyl residue of said FSH peptide, under conditions appropriate for the transfer.
2 . The method according to claim 1 , wherein R 1 -L has the formula:
wherein
a is an integer from 0 to 20.
3 . The method according to claim 1 , wherein R 1 has a structure that is a member selected from:
wherein
e and f are integers independently selected from 1 to 2500; and
q is an integer from 0 to 20.
4 . The method according to claim 1 , wherein R 1 has a structure that is a member selected from:
wherein
e, f and f′ are integers independently selected from 1 to 2500; and
q and q′ are integers independently selected from 1 to 20.
5 . The method according to claim 1 , wherein R 1 has a structure that is a member selected from:
wherein
e, f and f′ are integers independently selected from 1 to 2500; and
q, q′ and q″ are integers independently selected from 1 to 20.
6 . The method according to claim 1 , wherein R 1 has a structure that is a member selected from:
wherein
e and f are integers independently selected from 1 to 2500.
7 . The method of claim 1 , further comprising, prior to step (a):
(b) expressing said substrate follicle stimulating hormone peptide in a suitable host.
8 . The method of claim 1 , wherein said host is selected from an insect cell and a mammalian cell.