The attokatal measures extremely small amounts of catalytic activity, representing 10⁻¹⁸ katals. It is used in advanced biochemistry and molecular biology to quantify the reaction rates of single enzyme molecules or highly localized cellular processes. One attokatal corresponds to the conversion of one quintillionth of a mole of substrate per second.
Heard on the job
The single-molecule assay detected an activity level of roughly 1.5 attokatals.