Patent ID: 6136313
Filing Date: 2000-10-24
Classification: A61K,A61P,C07K,Y10S

Abstract:
An intermediate having the general formula:Fc--S--S--Xwherein:S--S is a disulphide bond;X is a terminal group which is protonated at a relatively low pH of about 5 or less, such that said disulfide bond to X, S--S--X, is electrophilic and susceptible to reduction at a pH of about 5 or less, at which pH other disulphide bonds are resistant to reduction; andFc is an Fc fragment, comprising four external sulphydryl groups, wherein said sulphydryl group on said Fc that is incorporated into said disulphide bond to X, S--S--X, is electrophilic and susceptible to reduction at a pH of about 5 or less, at which pH the three remaining external sulphydryl groups on said Fc are rendered by alkylation or incorporation into an interchain disulphide bond.