title: Preparation and properties of alpha- and epsilon-amino-protected porcine relaxin derivatives.
abstract: The chemical modification of the amino groups of B29 porcine relaxin resulted in pure derivatives of N alpha A1-citraconyl-B29 relaxin, N epsilon A7, N epsilon A16, N epsilon B8-tris [[[(methylsulfonyl)ethyl]oxy]carbonyl]-B29 relaxin (Msc3-relaxin), and N alpha A1, N epsilon A7, N epsilon A16, N epsilon B8-tetrakis [[[(methylsulfonyl)ethyl]oxy]carbonyl]-B29 relaxin (Msc4-relaxin). N alpha A1-Citraconyl-B29 relaxin was obtained after selective deprotection of fully acylated B29 relaxin derivatives. The quantitative reaction of N alpha A1-citraconylrelaxin with [[(methylsulfonyl)ethyl]-oxy]carbonyl succinimide ester followed by deprotection of the citraconyl group resulted in N epsilon A7, N epsilon A16, N epsilon B8-Msc3-B29 relaxin, the starting material for selective chemical modifications at the N terminus of the relaxin A chain. In mouse interpubic ligament assay both Msc3 and Msc4 derivatives of relaxin showed a bioactivity of 30%, while in the case of N alpha A1-citraconyl-B29 relaxin the bioactivity was reduced to 15%. When compared with unmodified relaxin, only the circular dichroic spectrum of N alpha A1-citraconyl-B29 relaxin revealed significant differences. Therefore, the loss in bioactivity of the N alpha A1-citraconyl-B29 relaxin seems to be related to the structural changes caused by the introduction of a negative charge at the N terminus of the A chain.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001681:Biological Assay; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D051379:Mice; D012065:Relaxin / Q000031:analogs & derivatives* / Q000302:isolation & purification; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D012065:Relaxin