Use of galactose oxidase for selective chemical conjugation of protractor molecules to proteins of therapeutic interest

A method for producing a conjugate of a glycoprotein having increased in vivo plasma half-life compared to the non-conjugated glycoprotein, the conjugate comprising a glycoprotein having at least one terminal galactose or derivative thereof, and a conjugating group covalently bonded thereto, the method comprising the steps of:

• (a) contacting a glycoprotein having at least one terminal galactose or derivative thereof with galactose oxidase to create a glycoprotein comprising an oxidized terminal galactose or derivative thereof having a reactive aldehyde functionality;
• and
• (b) contacting the glycoprotein product produced in step (a) with a reactant X capable of reacting with an aldehyde group;
• wherein reactant X comprises a group selected from the group consisting of Z′—CH2—Z″—R or Z′—CH2—Z″-L1-R;
• wherein R is a conjugating group;
• L1 is a linking moiety;
• Z′ and Z″ represent electron withdrawing groups;
• and one or both of the Z groups can be connected to the R group to create a conjugate represented by the formula (glycoprotein)(conjugating group).

A method for producing a conjugate of a glycoprotein having increased in vivo plasma half-life compared to the non-conjugated glycoprotein, the conjugate comprising a glycoprotein having at least one terminal galactose or derivative thereof, and a protractor group covalently bonded to the thereto through a linking moiety;

• the method comprising the steps of:
• (a) contacting a glycoprotein having at least one terminal galactose or derivative thereof with galactose oxidase to create a glycoprotein comprising an oxidized terminal galactose or derivative thereof having a reactive aldehyde functionality;
• (b) contacting the glycoprotein product produced in step (a) with a reactant X capable of reacting with an aldehyde group, wherein reactant X comprises a group selected from the group consisting of Z′—CH2-Z″—R or Z′—CH2-Z″-L1-R;
• wherein R is a conjugating group;
• L1 is a linking moiety;
• Z′ and Z″ represent electron withdrawing groups;
• and one or both of the Z groups can be connected to the R group and a linking moiety further comprising a second reactive, optionally protected, group to create a conjugate of the glycoprotein and the linking moiety;
• and
• (c) contacting the product of step (b) with a protractor group capable of reacting with the second reactive group of the linking moiety to create a conjugate represented by the formula (glycoprotein)-(linking moiety)-(protractor group).