title: Preparation of a crystalline tris-(N-methylpyridinium)-derivative of bovine insulin.
abstract: The reaction between 2-chloro-N-methylpyridinium iodide and bovine insulin at pH 8.5 afforded a trisubstituted derivative as main product. Following purification on DEAE-Sephadex A-25, this derivative crystallized from a citrate buffer in the form of large rhombohedra very similar to native insulin. This observation was confirmed by zero-layer X-ray precession photography. Amino acid analysis indicated substitution at the B1-terminus and on two of the four tyrosine residues. In the mouse convulsion assay the derivative showed no biological activity.
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange; D003460:Crystallization; D004586:Electrophoresis; D004589:Electrophoresis, Disc; D005260:Female; D007328:Insulin / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D008722:Methods; D051379:Mice; D011726:Pyridinium Compounds / Q000138:chemical synthesis; D014965:X-Rays
chemical_list: D007328:Insulin; D011726:Pyridinium Compounds