[Quantitative structure comparison of protein surfaces by micro-complement fixation].

Microcomplement fication (MCF) is a rapid and most sensitive method for the quantitation of slight modifications on protein surfaces not accessible by other immunologic means. Single amino acid substitutions (0.7 percent sequence differences) are readily detected. A firm relationship between sequence information and immunologic distance as measured by MCF could be established. The rate of molecular evolution of homology proteins can be derived from MCF measurements without prior knowledge of primary structures.