Enkephalin degradation by human erythrocytes and hemolysates studied using 1H NMR spectroscopy.
High resolution (400 MHz) 1H spin-echo NMR spectroscopy was used to monitor the degradation of leucine-enkephalin, and peptide fragments of it, by human erythrocytes and hemolysates. We showed that leucine-enkephalin is rapidly degraded by the cytosolic peptidases of the human erythrocyte, and we have elucidated the most probable pathway of degradation. Computer simulations of the proposed pathway, using a model incorporating the experimentally derived steady-state kinetic parameters obtained for the individual enzyme steps, showed close agreement with the experimental results. From a methodological perspective, the work demonstrates the value of 1H spin-echo NMR spectroscopy for rapidly elucidating, both qualitatively and quantitatively, an entire peptide-degradation pathway as it operates in situ.
D000595:Amino Acid Sequence; D004743:Enkephalin, Leucine / Q000097:blood*; D004912:Erythrocytes / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods
D004743:Enkephalin, Leucine