volume 32, issue 44, P11819-11824 1993
DOI: 10.1021/bi00095a010
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Daniel V. Santi, Tian Mei Ouyang, Anthony K. Tan, Donald H. Gregory, Thomas Scanlan, Christopher W. Carreras

Abstract: Pyridoxal 5'-phosphate (PLP) is an effective inhibitor of Lactobacillus casei thymidylate synthase (TS), competitive with respect to the nucleotide substrate dUMP (Chen et al., 1989). The UV/vis difference spectra of TS-PLP complexes show lambda max at 328 nm due to the specific interaction between Cys 198 of TS and PLP to form a thiohemiacetal, and lambda min at 388 nm due to depletion of free PLP. At high concentrations of PLP a new absorbance at 430 nm forms due to nonspecific Schiff base formation between …

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