Abstract
N-acetyltryptophan (AT) and caprylic acid (Cap) are known to suppress the heat-induced aggregation of
serum albumins. In this study, we examined the commonality of AT and Cap on the protein aggregation using hen
egg-white lysozyme, ovalbumin, and bovine γ-globulin (BGG), as well as bovine and human serum albumin. AT
and Cap as additives increased the unfolding temperatures of human and bovine albumins analyzed by far-UV
circular dichroism. Both AT and Cap highly suppressed the heat-induced aggregation of BGG as well as albumins,
while they enhanced the aggregation of lysozyme. In all cases, the addition of 100 mM ArgHCl showed no
synergistic effects with AT or Cap in suppressing the aggregation of BGG. The small chemicals of AT and Cap
will be useful additives toward the thermal stabilization of albumins and γ-globulin.
