Sulfonamides such as sulfamethoxazole tie up the enzyme pteridine synthetase while trimethoprim ties up the enzyme dihydrofolic acid reductase. As a result, tetrhydrofolic acid is not produced by the bacterium. (Purines = adenine, guanine)
Illustration of Pathway for the Synthesis
of Tetrahydrofolic Acid, a Cofactor
Needed for the Synthesis of DNA and RNA Nucleotides.jpg by Gary E. Kaiser, Ph.D.
Professor of Microbiology, The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at http://faculty.ccbcmd.edu/~gkaiser/index.html.
Last updated: September, 2018
Please send comments and inquiries to Dr. Gary Kaiser