Metal donation and apo-metalloenzyme activation by stable isotopically labeled metallothionein.
Coupled HPLC-ICP-MS has been used to quantitatively study the effects of GSSG and GSH on the ability of metallothionein (MTII) to donate essential and non-essential metals to apo-carbonic anhydrase. Stable isotopically labeled (67)Zn(3)Cd(4) MTII was used to enable Zn donated from MTII to be differentiated from extraneous sources of Zn. Transfer of both (67)Zn and Cd from MTII to apo-carbonic anhydrase was noted in the absence of either GSSG or GSH. GSSG increased the initial transfer of both Zn and Cd. Thereafter, a gradual increase in the (67)Zn content at the expense of Cd was noted over 24-h indicating continued interaction and exchange between MTII and the enzyme commensurate with the relative preferences shown by the proteins for these two metals. Although GSH also increased transfer of (67)Zn from MT it reduced the simultaneous transfer of Cd to the enzyme thereby conferring protection against Cd induced activation.
Mason
Andrew Z
AZ
Department of Biological Sciences and Institute of Interdisciplinary Research Materials, Environments and Society, California State University, Long Beach, CA90840 USA. zedmason@csulb.edu
Perico
Natalie
N
Moeller
Rhonda
R
Thrippleton
Kelly
K
Potter
Tiffany
T
Lloyd
Douglas
D
D002104:Cadmium / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism / Q000494:pharmacology*; D019803:Glutathione Disulfide / Q000378:metabolism / Q000494:pharmacology*; D013058:Mass Spectrometry; D008668:Metallothionein / Q000378:metabolism*; D015033:Zinc Isotopes / Q000378:metabolism
D015033:Zinc Isotopes; D002104:Cadmium; D008668:Metallothionein; D002256:Carbonic Anhydrases; D005978:Glutathione; D019803:Glutathione Disulfide