---
title: "Redox hopping"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "redox hopping"
aliases: ["incoherent hopping","electron hopping","redox conduction"]
first_seen: "2026-08-07T00:00:00.000Z"
writer_model: "claude-opus-4-8"
connects_to: ["extracellular electron transfer","Marcus theory","cytochrome","Geobacter sulfurreducens","metallic conduction"]
seek_code_commit: "649b1a4"
---


A charge-transport mechanism in which electrons move through a chain of discrete
redox cofactors — such as the stacked hemes of a multi-heme cytochrome — by a
series of thermally activated, non-adiabatic electron-transfer steps between
adjacent sites, each step governed by [[entity-marcus-theory|Marcus theory]].
Charge is localized on one cofactor and *hops* to the next; it is mechanistically
distinct from band-like or metallic conduction, where charge is delocalized
across the material rather than localized-and-hopping.

Matters to this vault as the physical mechanism the
*[[entity-geobacter-sulfurreducens|Geobacter]]* nanowire dispute turns on. The
cytochrome-polymer model holds that the filaments conduct by heme-to-heme
hopping ([[claim-geobacter-conductive-filaments-are-omcs-cytochrome-polymers]]);
the 2024 electrical-consistency challenge computes an upper bound on how much
current that hopping can carry and finds the measured conductivities far exceed
it ([[claim-2024-paper-disputes-geobacter-cytochrome-nanowire-conductivity]],
[[claim-guberman-pfeffer-0-14-pa-ceiling-is-computed-not-measured]]). It is the
foil to the *non-redox*, metal-like conduction reported for cable bacteria
([[claim-cable-bacteria-conduct-through-nickel-protein-wire]]) — two different
answers to how a protein wire can move an electron. Both sit under
[[entity-extracellular-electron-transfer|extracellular electron transfer]].

## References
- [[claim-geobacter-conductive-filaments-are-omcs-cytochrome-polymers]]
- [[claim-2024-paper-disputes-geobacter-cytochrome-nanowire-conductivity]]
- [[claim-guberman-pfeffer-0-14-pa-ceiling-is-computed-not-measured]]
- [[claim-guberman-pfeffer-blames-measurement-not-cytochrome-identity]]
- [[claim-cable-bacteria-conduct-through-nickel-protein-wire]] (contrasting non-redox, metallic mechanism)