Antipeptide antibodies to the porcine lactate dehydrogenase isoenzyme M4 active center fragment as a probe for the structural analysis of active centers of human lactate dehydrogenase isoforms

Antipeptide antibodies (AB) to the fragment of the active center of porcine lactate dehydrogenase M4 isoform were used for the analysis of antigenic properties and structural comparison of active centers of human lactate dehydrogenase isoforms. Selective precipitation of the M-subunit-containing isoforms using an immunoadsorbent based on antipeptide AB as well as selective inhibition of the enzymic activity of the M4 isoform by antipeptide AB testify to the specific binding of isoforms to antipeptide AB. The experimental results confirm the literary data on conformational changes in the structure of the active centers of corresponding human lactate dehydrogenase isoforms. The specific interaction of antipeptide AB with human lactate dehydrogenase isoforms suggests that the site of the amino acid sequence (residues 180-214) in both human and porcine M4 isoenzymes is immunochemically identical. The data obtained suggest that antipeptide AB are convenient probes for detecting differences (including minor ones) in the primary and spatial structure of enzymes.