Rabbit liver metallothionein subisoform characterisation using liquid chromatography hyphenated to Diode Array Detection and Electrospray ionisation mass spectrometry
The direct electro spray ionisation mass spectrometry ESI/MS infusion of rabbit liver MI and of its two isoforms in an acidic medium has allowed the identification of the already sequenced (apo) subisoforms MT-1a, MT-2a, 2b, 2c, 2d and 2e, but also shows the presence of minor quantities of non acetylated subisoforms and that of unsequenced forms, Using the hyphenated system RP-HPLC-PDA-ESI/MS, the non acetylated apoforms have been shown to have different retention times than their corresponding acetylated forms. In many cases, a single molecular mass and therefore a single compound can be attributed to each chromatographic peak (case of aposubisoforms), but this is not always the case as some HPLC peaks obviously contain several species which are very often different complexes of the same subisoform at a particular pH, Interestingly, the results show clearly that the non acetylated forms are the first species which start to be complexed, first by Cu and then by Cd. When the pH increases from 1.7 to 5 and this holds true for all subisoforms. For their part, the major acetylated subisoforms such as MT-1a, MT-2a or MT-2e starts to be significant. complexed at higher pH values (around pH 4). As a general consideration, it should be stressed that working at the subisoform level should be more and more a prerequisite for any thinking on rnetallothionein chemistry.
Bibliographic Reference: An article published in: Chromatographia Vol. 52 (December 2000), pp. 745-752
Record Number: 200013266 / Last updated on: 2001-05-15
Original language: en
Available languages: en