Monoclonal antibodies to monomeric rat liver metallothionein-I: the immunoreactivity of lysine residues in metallothionein.
Regardless of the weak immunological response against the low-Mr metallothioneins (MTs) the production of murine monoclonal antibodies (mAbs) to monomeric rat liver MT-I was successful. ELISA revealed two groups of mAbs which exhibited different specificities as examined on the native and the lysine-residue modified antigen (Ag). One "lysine-directed mAb" group, consisting of three mAbs, exhibited a specific immunoreactivity with the lysine-containing epitopes of MTs. Their role in the antigenicity of MTs was examined by modifying these residues using glutaraldehyde (GA). Titration with GA resulted in a progressive decline in Ag recognition in the immunoblot; this was completely leveled off when equimolar concentrations were reached. A similar response employing the GA-modified protein in the ELISA was noticed. The second group of mAb cross-reacted with various MTs of different origin, indicating that the common, lysine-free NH2-terminus is exclusively recognized. In direct ELISA of cross-linked MTs, the observed reactivities were much more pronounced. Iodoacetamide (IA) modification of the lysines confirmed the above observations of the GA-derived Ag. Notably, the immunoreactivity was not affected when the cysteine residues were IA-carboxymethylated, nor did the subsequent loss of metals diminish the immunological response in the immunoblot.
Nagel
W
W
Anorganische Biochemie, Physiologisch-Chemisches Institut, Universität Tübingen, F.R.G.
Hartmann
H J
HJ
Weser
U
U
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D008099:Liver / Q000737:chemistry*; D008239:Lysine; D008668:Metallothionein / Q000737:chemistry / Q000276:immunology*; D051379:Mice; D051381:Rats
D000911:Antibodies, Monoclonal; D000939:Epitopes; D008668:Metallothionein; D008239:Lysine