Influence of aliphatic amines on the interaction of human C′1 with EAC′4

Abstract

The activity of human C′1 fixed to EAC′4 cells (EAC′1 hu4) was decreased by treatment with alkylamines. The ability of butanediamine to reduce the C′1 was substantially greater than the corresponding monoamine. The ammonium ion by itself, i.e. lacking an alkyl radical, was without effect on EAC′1 hu4). In comparing several alkyldiamines with the amino groups present on the first and last carbons, it was found that those compounds with three to eight carbons were essentially equally effective, but that the two carbon compound had only about one-half the C′1-reducing ability. This lesser activity of ethylenediamine compared to the longer compounds was due to a difference in pK's. The pH at which the experiments were normally run (7·3) allowed the longer compounds such as butanediamine, but not ethylenediamine, to be fully protonated. When the experiments were carried out at a pH sufficiently low (6·0) to allow full protonation of ethylenediamine as well as butanediamine, the two compounds were equally active.