Molecular Biology

Protein Interactions

Sigma® has prepared product lists for commonly used protocols from Cold Spring Harbor Protocols.

  View the protocol on BioSupplyNet.com.

Selected Protocol from "Protein-Protein Interactions: A Molecular Cloning Manual, 2nd Edition,", Erica A. Golemis and Peter D. Adams.

View the protocol "Protein Interactions Captured by Chemical Cross-linking: One-Step Cross-linking with Formaldehyde" at BioSupplynet.com

Owen W. Nadeau and Gerald M. Carlson

ABSTRACT
This protocol describes a method for chemical cross-linking of proteins using formaldehyde. With the exception of zero-length cross-linkers, formaldehyde has the shortest cross-linking span (~2-3 Å) of any cross-linking reagent, thus making it an ideal tool for detecting specific protein-protein interactions with great confidence. Despite its simple chemical structure (CH2O), formaldehyde’s single carbonyl group functions essentially as a homobifunctional reagent and is capable of conjugating targets through two different chemical pathways. In Mannich-type reactions, which typically require elevated temperatures (37 °C or above) for a period of 2-24 hours for acceptable yields, formaldehyde condenses with amines (1°, 2°, or salts of ammonia) and compounds with active hydrogens to form stable cross-links. Formaldehyde also reacts with amines to form highly reactive immonium cations that are reactive toward protein-containing nucleophiles, including sulfhydryls, amines, phenols, and imidazoles. The latter reaction is more rapid than the former and is generally the more predominant in typical protein cross-linking reactions at ambient temperatures.

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Products Available for this Protocol

Protocol Material Description Product #  Product Name Add to Cart
SDS L4390 Sodium dodecyl sulfate, for molecular biology, ≥98.5% (GC)
Paraformaldehyde 158127 Paraformaldehyde, powder, 95%
HEPES H4034 HEPES, Biotechnology Performance Certified, ≥99.5% (titration), cell culture tested
EDTA E5134 Ethylenediaminetetraacetic acid disodium salt dihydrate, for molecular biology, ≥99%

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