“…44 There has been extensive research done on electron transfer in proteins [45][46][47] especially in well-characterized model systems such as cytochrome c, 48 plastocyanin 49 , and azurin. [50][51][52][53] Other studies have explored the solid state electronic transport properties of proteins whose mechanisms of action rely on electron transfer, ET. 54,55 Several books, 28,[54][55][56][57][58][59] recent special issues of journals (from which we cite results published therein 51,60 ), and reviews 51,61,1,47,62,63 have appeared over the years, going back to the early 64 In parallel, the area of ET has remained very active, and we rely heavily in this review on our present understanding of ET to discuss what can be learned from protein bioelectronics devices.…”