Chemical crosslinkers
Disclosed herein are methods of chemical conjugation comprising contacting a lysosomal enzyme with a first crosslinking agent to introduce aldehyde groups; contacting a lysosomal targeting peptide with a second crosslinking agent to introduce a hydrazide group at the N-terminal residue; contacting the lysosomal enzyme with aldehyde groups of step a. with the lysosomal targeting peptide with a hydrazide group at the N-terminal residue of step b; and forming a lysosomal enzyme-lysosomal targeting peptide conjugate.
1. A lysosomal targeting peptide, comprising a variant human IGF-2 having the sequence set forth in SEQ ID NO:1 with the following modifications:
deletion of amino acids 1-4,
substitution of arginine for glutamic acid at position 6,
substitution of leucine for tyrosine at position 27;
and optionally the following modifications:
substitution of arginine for lysine at position 65.
2. The lysosomal targeting peptide of claim 1 , comprising the amino acid sequence of SEQ ID NO:2.
3. The lysosomal targeting peptide of claim 1 or 2 , further comprising a linker.
4. The lysosomal targeting peptide of any of claim 1 , wherein the variant human IGF-2 comprises the amino acid sequence of SEQ ID NO:3.
5. The lysosomal targeting peptide of any of claim 1 , wherein the variant human IGF-2 comprises the amino acid sequence of SEQ ID NO:4.
6. The lysosomal targeting peptide of any of claim 3 , wherein the linker is at the N-terminal end of the variant human IGF-2.
7. The lysosomal targeting peptide of any of claim 3 , wherein the linker is at the C-terminal end of the variant human IGF-2.