The Enzymatic Oxidation of Graphene Oxide

The Enzymatic Oxidation of Graphene Oxide Gregg P. Kotchey,1 Brett L. Allen,1 Harindra Vedala,1 Naveena Yanamala,2,3 Alexander A. Kapralov,2 Yulia Y. Tyurina,2 Judith Klein-Seetharaman,3 Valerian E. Kagan,2 and Alexander Star*,1 1 Department of Chemistry, 2Department of Environmental and Occupational Health, 3Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260 Email: [email protected] Supporting Information Table of Contents Figure S1 – TEM Micrographs ............................................................................................................ S-2 Figure S2 – Amplex Red Assay for CCG ............................................................................................ S-3 Figure S3 – EPR Data ........................................................................................................................... S-4 Figure S4 – AFM Images with Section Analysis ................................................................................. S-5 Table S1 – Predicted Interaction Sites for CCG, GO and Holey GO on HRP ............................... S-6 Figure S5 – Back Gate FET Data for hRGO and RGO ..................................................................... S-7 Figure S6 – (a) FT-IR and (b) UV-Vis Spectra ................................................................................... S-8 S1 F Figure S1. TEM micro ographs of (aa) graphene oxide-controol I (–H2O2) and (b) graaphene oxidee-control I (–HRP) affter 10 days of incubatioon. TEM miicrographs of II o (c) reducedd graphene oxide o (RGO O)-control I (–H2O2) annd (d) RGO-ccontrol II (––HRP) after 10 1 days of inncubation. (e) ( Holey graaphene oxide formed b adding 40 µM H2O2 (final conccentration) every by e 30 minnutes for 4.5 hours to a dispersionn initially c containing g graphene oxiide and HR RP. (f) “Oveer-oxidized”” graphene oxide o formeed by using identical c conditions ass (e). (g) Holey reducedd graphene oxide o (hRGO O) formed by b chemically reducing the t holey g graphene oxiide formed after a 8 day of o incubationn with HRP/H H2O2 with hyydrazine. S2 F Figure S2. Amplex Red R UV-Vis spectroscoppic study coonducted onn days 1 andd 20 of the reduced g graphene oxiide (RGO)/H HRP/H2O2 saample. S3 F Figure S3. Electron paaramagneticc resonance (EPR) specctroscopy daata. To eachh sample coontaining H HRP (0.35 µM) µ and etop poside (200 µM), H2O2 (80 µM) waas added, andd either a fuull ESR specttra (a) or t time couurse of the EPR signal (bb-e) were reccorded. Thee duration off the recordiings were 100 min for the s sample (a), and 1 min for f the time course of the t EPR siggnals (b-e). Sample (d) contained graphene g o oxide (5×10-5 mg/ml), an nd sample (ee) contained reduced grapphene oxidee (RGO) (5×10-5 mg/ml).. S4 F Figure S4. Atomic force microscoopy (AFM) images i withh section anaalysis of (a) graphene oxide, o (b) h horseradish peroxidase (HRP), andd (c) reducedd graphene oxide (RGO O). The heeights determ mined by s section analyysis are 0.61 nm, 5.02 nm m, and 1.73 nm, respectiively. S5 Table S1: Details of the Predicted Interaction Sites for Reduced Graphene Oxide, Graphene Oxide and Holey Graphene Oxide on HRP. Binding Site 1 Structure Reduced Graphene Oxide Graphene Oxide Holey Graphene Oxide Binding Site 2 Binding Energy Residues with in 5Å Binding Energy Residues with in 5Å -26.7 kcal/mol Asn24, Arg27, Ser28, Asp29, Asp56, Asn57, Thr58, Thr59, Arg62, Asp66, Asn72, Pro78, Asp81, Arg82, Ala85, Arg178, Ser216, Ala217, Asn214, Gly213, Asn300, Arg302, Val303, Val304, Ser306 - - -24.8 kcal/mol Asn24, Glu25, Arg27, Ser28, Asp56, Asn57, Thr58, Thr59, Phe77, Pro78, Val79, Asp81, Arg82, Ala85, Ala86, Glu88, Ser89, Pro92, Lue299, Asn300, Arg302, Val303, Val304, Ser306 -22.4 kcal/mol Leu26, Arg27, Pro30, Lys174, Thr200, Tyr201, Gln203, Thr204, Leu205, Arg206, Gly207, Leu208, Pro210, Leu218, Asp220, Leu223, Arg224, Thr225, Pro226 Thr227, Ile228, Lys241 -22.4 kcal/mol Ser28, Asp29, Pro30, Lys174, Thr200, Tyr201, Gln203, Thr204, Leu205, Arg206, Gly207, Leu208, Pro210, Leu211, Asn212, Gly213, Asn214, Ala217, Leu218, Val219, Asp220, Asp222, Leu223, Arg224, Thr225, Pro226, Thr227, Ile228 - - S6 Figure S5. (a) Conducctivity versus potential (bback gate) plot p for reducced graphene oxide (RG GO, black c circles) and holey reduceed graphenee oxide (hRG GO, solid redd line). Thee measuremeents were reccorded at a constant drrain-source voltage v of 10 mV. Inseet representss a schematicc of the expperimental seetup. (b) T Transfer chaaracteristics (Gate voltagge (VG) versus Conductaance (G)) off RGO (blackk circles) annd hRGO ( (solid red linne) measured d under ambiient conditioons and a connstant drain--source voltaage of 50 mV V. S7 F Figure S6. (a) FT-IR spectra of holey reducced graphenne oxide (hR RGO), reduuced graphenne oxide ( (RGO), and graphene ox xide. (B) UV V-Vis spectra of hRGO, RGO, and graphene g oxiide. S8