Initial quality assessment and qualitative interpretation of protein film electrochemistry catalytic data

When a redox enzyme is wired to an electrode under conditions of direct electron transfer (DET), its activity can be simply detected as a current. This approach has been reviewed extensively, but here we address a gap in the literature by discussing the initial qualitative interpretation and assessment of catalytic DET electrochemical data. Topics addressed here include electroactive coverage, turnover frequencies, mass transport limitations, film loss, redox-driven (in)activation, signal corrections, distinction between steady-state and transient responses, and identification of non-ideal behaviors. Based on our group's expertise, we provide explanations, general advice, and prescriptive guidance to help readers understand experimental issues.