Editing of the non-protein amino acid homocysteine, a frequent type of error-correcting
process in amino acid selection for protein synthesis by an aminoacyl-tRNA synthetase,
results in formation of a cyclic thioester, homocysteine thiolactone. Here it is shown that
human cells in which homocysteine metabolism is deregulated by a mutation in the
cystathionine β-synthase gene and/or by an antifolate drug, aminopterin (which prevents
remethylation of homocysteine to methionine by methionine synthase), produce more …