This definition appears rarely
where the following standard abbreviations apply: NMDG, N-methyl-D-glucamine; Tris, tris[hydroxymethyl]aminomethane; HEPES, N-[2-hydroxyethyl]piperazine-N-[2-ethanesulfonic acid]; MOPS, 3-[N-morpholino]propanesulfonic acid; MES, 2-[N-morpholino]ethanesulfonic acid. The estimated error in the measurements from Ng and Barry4 was considered to be less than about 0. 005. EGTA(2-) and EGTA(3-) are from Keramidas et al.