Murine monoclonal antibody TU-01 specific for tubulin (Viklický et al., 1982, Cell. Biol. Int. Rep. 6, 725; Dráber et al., in prep.) also recognizes a determinant in denatured reduced human serum albumin and in some peptides produced by its partial enzymatic cleavage, but does not react with serum albumins of several other species tested. Several other anti-tubulin monoclonal antibodies do not exhibit such a cross-reactivity.