Novel compounds of the general formula:
in which X represents a polymer,
Q represents a linking group;
W represents an electron-withdrawing moiety or a moiety preparable by reduction of an electron-withdrawing moiety;
each of R
1
and R
2
independently represents a hydrogen atom or a C
1-4
alkyl group; and
either Z
1
represents a protein or a peptide linked to CR
2
via a nucleophilic moiety, and Z
2
represents a molecule linked to CR
2
via a nucleophilic moiety, or Z
1
and Z
2
together represent a single group derived from a protein or peptide linked to CR
2
via two nucleophilic moieties.
Novel compounds of the general formula (I): in which X represents a polymer; Q represents a linking group; W represents an electron-withdrawing moiety or a moiety preparable by reduction of an electron-withdrawing moiety; each of R1 and R2 independently represents a hydrogen atom or a C1-4alkyl group; and either Z1 represents a protein or a peptide linked to CR2 via a nucleophilic moiety, and Z2 represents a molecule linked to CR2 via a nucleophilic moiety, or Z1 and Z2 together represent a single group derived from a protein or peptide linked to CR via two nucleophilic moieties.