PT523 and other aminopterin analogs with a hemiphthaloyl-L-ornithine side chain: exceptionally tight-binding inhibitors of dihydrofolate reductase which are transported by the reduced folate carrier but cannot form polyglutamates.

PT523 and other aminopterin analogs with a hemiphthaloyl-L-ornithine side chain: exceptionally tight-binding inhibitors of dihydrofolate reductase which are transported by the reduced folate carrier but cannot form polyglutamates.