when reaction mixtures were submitted to sodium dodecyl sulfate-polyacrylamide gel electrophoresis to separate the alpha- and beta-chains of the heterodimeric tubulin molecule , the alpha-chain of free tubulin , but not intact microtubules , was the preferential site of stable adduct formation under both reductive and nonreductive conditions .
C3539817
beta-chains
C0026046
microtubules