1H NMR spin-echo spectroscopy of human erythrocytes. Transformation of exogenous compounds.

1H NMR spin-echo spectroscopy has been used to study the metabolism of exogenous compounds in human erythrocytes. The non-invasive nature of the technique and the continuous monitoring makes it ideal to investigate both the conversion of substrates and the occurrence and the nature of the products. Hydrolysis rates may be determined and the hydrolysis of alkyl, vinyl, and aryl acetates are shown to be due to A-esterase activity. The conversion products are normally observed, but in the case of dimethyl phthalate and methyl acetate only part of the methanol is found. An interesting case is the hydrolysis of vinyl acetate and the consecutive conversion of the vinyl alcohol to acetaldehyde (hydrate). Coupling of glutathione to a variety of vinyl derivatives is also observed. Oxidation of acetaldehyde can also be followed. Styrene and 5-chloro-2-methylaniline are slowly converted in what is believed to be oxidation reactions. Changes in 1H chemical shifts are observed for a number of compounds upon uptake into human erythrocytes, a shift that is suggested to be due to binding to haemoglobin.