Sulfa Drugs and Folic Acid Analogs
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Sulfa Drugs and Folic Acid Analogs
Sulfa Drugs and Folic Acid Analogs
Sulfa Drugs
Sulfanilamide was the first antibacterial agent. Many other sulfa drugs (such as sulfamethoxazole) have since come into use.
The Chink in the Armor
Both bacteria and their human hosts require folic acid for
* nucleic acid synthesis (it is converted into purines and thymidine) as well as
* protein synthesis (precursor of the amino acids methionine and glycine)
However,
* bacteria synthesize their folic acid starting with para-aminobenzoic acid (PABA), while
* we must ingest our folic acid already formed; that is, for us it is a vitamin.
Sulfanilamide, and the other sulfa drugs, are analogs of PABA; they compete with PABA and, when chosen, block the synthesis of folic acid. Mammals ignore PABA and its analogs and thus can tolerate sulfa drugs.
Folic Acid Analogs
These synthetic molecules block the final step in the conversion of
PABA to folic acid so they, too, block nucleotide and protein synthesis
in bacteria but not in mammals.
Trimethoprim is one of several in current use. These folic acid analogs are often used in combination with a sulfa drug.
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Sulfa Drugs
Sulfanilamide was the first antibacterial agent. Many other sulfa drugs (such as sulfamethoxazole) have since come into use.
The Chink in the Armor
Both bacteria and their human hosts require folic acid for
* nucleic acid synthesis (it is converted into purines and thymidine) as well as
* protein synthesis (precursor of the amino acids methionine and glycine)
However,
* bacteria synthesize their folic acid starting with para-aminobenzoic acid (PABA), while
* we must ingest our folic acid already formed; that is, for us it is a vitamin.
Sulfanilamide, and the other sulfa drugs, are analogs of PABA; they compete with PABA and, when chosen, block the synthesis of folic acid. Mammals ignore PABA and its analogs and thus can tolerate sulfa drugs.
Folic Acid Analogs
These synthetic molecules block the final step in the conversion of
PABA to folic acid so they, too, block nucleotide and protein synthesis
in bacteria but not in mammals.
Trimethoprim is one of several in current use. These folic acid analogs are often used in combination with a sulfa drug.
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