1

Electronic supplementary information for

Attila Jancsó, Zoltán Paksi, Noémi Jakab, Béla Gyurcsik, Antal Rockenbauer and Tamás

Gajda*

Solution chemical properties and catecholase-like activity of the copper(II)-Ac-His-His-

Gly-His-OH system, a relevant functional model for copper containing oxidases

Figure S1. pH dependence of the UV-Vis spectra (A) of the copper(II)–hhgh system ([CuII] =

[hhgh] = 0.7 mM, T = 298 K, I = 0.1 M NaCl, pH = 2.6-11.0), and the individual electronic

absorption spectra of the formed species (B).

0.0

0.1

0.2

0.3

0.4

0.5

300 400 500 600 700 800

Wavelength (nm)

A

A

300 400 500 600 700 8000

100

200

300 B� � � �� � � �� � � � �� � � � �� � � � �� �(M-1 c

m-1)

Wavelength (nm)

2

Figure S2. Calculated EPR spectra of the individual species formed in the copper(II)-hhgh

system

2800 3000 3200 3400

Magnetic field (G)

Cu(II)

CuHL

CuL

CuH-1L

CuH-2L(a)

CuH-2L(b)

CuH-3L

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Figure S3: Inhibition of the Nitroblue Tetrazolium (NBT) reduction as a function of the

copper(II) concentration in 0.05 M phosphate buffer (�: [Cu2+

] = [hhgh], pH = 6.8; �:

[Cu2+

] = [hhgh], pH = 7.5; �: [Cu2+

] = 0.1[hhgh], pH = 7.5). The inhibition caused by Cu,Zn-

SOD is shown in the insert. The following species are present in the solutions:

Cu2+

(32%), CuL (35%) and CuH–1L (28%) at pH 6.9 and [Cu2+

] = 0.95[hhgh] = 0.2 µM;

Cu2+

(10%), CuL (19%), CuH–1L (56%) and CuH–2L (13%) at pH = 7.5 and [Cu2+

] =

0.95[hhgh] = 0.2 µM;

CuL (20%), CuH–1L (63%) and CuH–2L (16%) at pH = 7.5 and [Cu2+

] = 0.1[hhgh] = 0.2 µM.

0 2x10-8

4x10-8

6x10-8

0

20

40

60

80

100

% inhibition

[Cu,Zn-SOD] (M)

0.0 2.5x10-7

5.0x10-7

7.5x10-7

1.0x10-6

0

20

40

60

80

100

% Inhibition

[Cu2+] (M)

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Figure S4. The CD spectra of the copper(II)–hhgh system ([CuII] = [hhgh] = 0.055 mM, T =

298 K, I = 0.1 M NaCl, pH = 7.8-12.03) at different pH in 86 w% methanol-water solvent

mixture. The calculated ∆ε values are based on the total metal ion concentration.

-0.9

-0.6

-0.3

0.0

0.3

0.6

0.9

300 350 400 450 500 550 600

Wavelength (nm)

∆ε (

∆ε (

∆ε (

∆ε (M

-1cm-1)

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Figure S5. The pH dependence of the average CD intensity between 355 and 365 nm (the

maximum detected for the spectrum of the species CuH–2L). The solid line was calculated

using pK1 = (9.6 ± 0.1) and pK2 = (11.0 ± 0.2).

0

0.2

0.4

0.6

0.8

7.5 8.5 9.5 10.5 11.5 12.5

pH

∆ε

∆ε

∆ε∆ε (M-1cm-1)