Section 11
Chapter 10,980

Methods for dual, site-specific derivatization of bovine pancreatic trypsin inhibitor: trypsin protection of lysine-15 and attachment of fatty acids or hydrophobic peptides at the N-terminus

Pool, C.T.; Thompson, T.E.

Bioconjugate Chemistry 10(2): 221-230


ISSN/ISBN: 1043-1802
PMID: 10077471
DOI: 10.1021/bc9800771
Accession: 010979910

To produce a series of model membrane proteins, bovine pancreatic trypsin inhibitor (BPTI) has been modified by specifically attaching reporter groups to Lys-15 and fatty acids or hydrophobic peptides at the N-terminus. Lys-15 of BPTI was protected by trypsin bound to BPTI, then O-methylisourea (OMIU) was used to guanidinate all unprotected lysines. The N-terminal amine was then reacted with several saturated fatty acid anhydrides from 8 to 18 carbons in length, or with an SMCC cross-linker. Cysteine-containing hydrophobic peptides, cleaved from resin in the presence of sodium dodecyl sulfate (SDS), were then attached to the protein via the N-terminal cross-linker. The methods described yield a unique, chemically modified protein which can carry site-specific modifications at two distinct residues. The resulting proteins are ideal for diffusional or partitioning studies on model and biological membranes.

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