title: Protein-polymer grafts, IV. A. Modification of amino acids: IIai. Modification of free lysine with reductive arylation.
abstract: Inability to increase the yield of reaction between 2,4 dihydroxybenzaldehyde and gelatin beyond 55 and 60% has led to an extensive investigation of reductive alkylation with free lysine. Even with free lysine, the extent of reaction was about 60%. Since this could be attributed to the electron donation by the phenolic hydroxyls, reductive alkylation was performed between o-, m-, and p-nitrobenzaldehydes and free lysine; o- and m-nitrobenzaldehyde were ineffective in increasing the yield while with p-nitrobenzaldehyde a yield of 72% was achieved. The unreacted 28% of the lysines are susceptible to epichlorohydrin. These results suggest that the slow, reversible first step in reductive alkylation, the formation of the Schiff's base, is responsible for the low yield.
authors.affiliation: Center for Protein Research, Albert Einstein Medical Center, Philadelphia, PA.
authors.forename: K
authors.initials: K
authors.lastname: Kaleem
authors.forename: F
authors.initials: F
authors.lastname: Chertok
authors.forename: V S
authors.initials: VS
authors.lastname: Nithianandam
authors.forename: S
authors.initials: S
authors.lastname: Erhan
mesh_terms: D000478:Alkylation; D001547:Benzaldehydes; D007202:Indicators and Reagents; D008239:Lysine / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction
chemical_list: D001547:Benzaldehydes; D007202:Indicators and Reagents; C029915:4-nitrobenzaldehyde; D008239:Lysine