Submitted to: Biochemical Society Transactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/1995
Publication Date: N/A
Citation: Interpretive Summary: Metalloproteins play many important roles in processes that are basic to cellular function such as respiration, metabolism and gene expression. In order to fully characterize the function of a particular metalloprotein, it is necessary to understand something about the binding of the metal(s) to the protein. Metallothionein (MT) is a class of metal-binding proteins with masses ranging from 6000 to 7000 daltons. MTs have been reported to play an important role in cellular metal metabolism and they have been actively studied for a number of years. Currently there are no analytical methods that can accurately characterize the size and the type and amount of metal bound to different MTs. Using the coupled analytical technique of high performance liquid chromatography-high resolution electrospray mass spectrometry we now report on a rapid an highly precise method to characterize different MT isoforms with respect to the size of the protein and the nature of the metals bound to it. Such information is very useful in further defining the function of MTs in metal metabolism.
Technical Abstract: Mellothioneins (MT) are a family of low Mr metal-binding protein isoforms which are found in most organsims. These proteins may play a role in Zn homeostasis, in the acute phase response and as an antioxidant but it is not clear how many isoforms are expressed and whether they perform distinct functions. The isoform heterogeneity and metal-binding characteristics for sheep MT have been studied by on-line reversed-phase HPLC-electrospray ionisation/MS. Mass spectra reveal 4 major isoforms of apo-mass 5993-6070 and up to 6 additional putative minor isoforms. Stable metal-binding forms of these MT isoforms were identified.