Regenerative silver nanoparticles for SERRS investigation of metmyoglobin with conserved heme pocket

Reply to the comment on “Sensitive marker bands for the detection of spin states of heme in surface-enhanced resonance Raman scattering spectra of metmyoglobin”

“…1 Indeed, the SERRS peak was observed at 1490 cm −1 , which is assigned to 5-coordinated heme b in the high spin state, by excitation at 406.7 and 413 nm (Soret band), while the corresponding RRS (ν 3 ) peak of native met-Mb appeared at 1480 and 1510 cm −1 , which is attributed to 6-coordinated heme b in the high and low spin state, respectively. [3][4][5] By the interaction with the Ag surface, conformation of heme c in cytochrome c is changed and is then reflected in the spectra. 6 In our paper, 2 however, Fig.…”

Comment on “Sensitive marker bands for the detection of spin states of heme in surface-enhanced resonance Raman scattering spectra of metmyoglobin” by Y. Kitahama, M. Egashira, T. Suzuki, I. Tanabe and Y. Ozaki

“…Surface functionalization of the metal nanoparticles has been shown to be an alternative way to keep myoglobin in its native form. 13 For a correct interpretation of the spectra shown in Fig. 3, a comparison should be made with the SERRS spectra of protein-free Fe-protoporphyrin IX 14 on a silver electrode at the same laser excitation wavelength (514.5 nm), or with the SERRS spectra of the related compound hematin 15 excited at 532 nm: the spectra are very similar, which suggests that the authors have detected the SERRS spectrum of silver-adsorbed hemin.…”

“…[11][12][13] It has been shown in detail that the interaction between citrate-containing Ag colloids and met-myoglobin, which has a six-coordinate high-spin Fe-protoporphyrin IX under normal experimental conditions, gives rise to the SERRS spectrum of a pentacoordinated species. This interpretation does not take into account previous experimental work performed in distinct laboratories through several decades.…”

“…This interpretation does not take into account previous experimental work performed in distinct laboratories through several decades. 13 For a correct interpretation of the spectra shown in Fig. This has been attributed to the formation of a μ-oxo dimer, due to heme detachment from the protein matrix.…”

“…This interpretation does not take into account previous experimental work performed in distinct laboratories through several decades. [11][12][13] It has been shown in detail that the interaction between citrate-containing Ag colloids and met-myoglobin, which has a six-coordinate high-spin Fe-protoporphyrin IX under normal experimental conditions, gives rise to the SERRS spectrum of a pentacoordinated species. This has been attributed to the formation of a μ-oxo dimer, due to heme detachment from the protein matrix.…”