Interactions of arsenic with human metallothionein-2.
Arsenic is a toxic element that is found in the atmosphere, as well as in aquatic and terrestrial environments. We have demonstrated that As(3+) binds to human metallothionein-2 (hMT-2) by UV absorption spectroscopy, inductively coupled plasma-atomic emission spectrometry (ICP-AES), and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). MALDI-TOF-MS revealed that the structure of the adduct formed by arsenic and hMT-2 (As-hMT-2) was not homogeneous. The maximum molar ratio of arsenic to hMT-2 was found to be more than 6:1 on ICP-AES, UV absorption spectroscopy and MALDI-TOF-MS. The ratio of the number of sulfhydryl groups in hMT-2 that bound arsenic was 3:1, which is the same as the ratios reported previously for arsenic-glutathione and arsenic-phytochelatin complexes.
Toyama
Mitsutoshi
M
Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamada-oka, Suita, Osaka 565-0871, Japan.
Yamashita
Mitsuo
M
Hirayama
Noriaki
N
Murooka
Yoshikatsu
Y
D000818:Animals; D001151:Arsenic / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008668:Metallothionein / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D011993:Recombinant Fusion Proteins; D008668:Metallothionein; D001151:Arsenic