Possible Interaction: Para-aminobenzoic acid (PABA) and Aminosalicylic Acid

“ p-Aminosalicylic acid (… pABA transport competitively, with a inhibition constant of 378 nM. Phloritin, flufanamic acid, and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DITS), which are … transporter (band 3), and oxalic acid, a substrate of this transporter, partially inhibit pABA transport into both normal and infected red cells.”

“Durham and Hubbard (1959) suggested that p-aminosalicylic acid influenced the assimilation of p-aminobenzoic acid by competing with the substrate for the specific transport mechanism(s) in the cell membrane thereby controlling oxida-”

“More recently, Hedgecock (1958) demonstrated that p-aminobenzoic acid competitively antagonized the inhibitory effect of p-aminosalicylic acid on the growth of Mycobacterium tuberculosis.”

“Results obtained from additional investigations indicated that the utilization of p-aminobenzoic acid as a sole source of energy for aerobic growth is also competitively inhibited by paminosalicylic acid (Durham, 1957).”

“That para-aminobenzoic acid antagonizes competitively the inhibitory effect of paraaminosalicylic acid on the growth of Mycobacterium tuberculosis is well known.”

“The observation by Youmans et al. (1947) that para-aminobenzoic acid (PABA) antagonizes the action of para-aminosalicylic acid (PAS) has been confirmed repeatedly.”

“It is known that intrinsic metabolites, such as, para-aminobenzoic acid (PABA) and methionine, antagonize PAS and structurally related anti-folate drugs.”

“Based on the observation that exogenously supplied p-aminobenzoic acid (PABA) can antagonize the action of antifolates that interact with dihydropteroate synthase (DHPS), such as sulfonamides and p-aminosalicylic acid (PAS), we hypothesized that bacterial PABA biosynthesis contributes to intrinsic antifolate resistance.”

“Herein, we demonstrate that disruption of PABA biosynthesis potentiates the anti-tubercular action of DHPS inhibitors and PAS by up to 1000 fold.”

“This could account for why p-aminobenzoic acid , but not salicylic acid, antagonizes the action of p-aminosalicylic acid.)”

“Antagonistic effects of PABA on the tuberculostatic activities of synthesized ω-substituted alkyl esters of PAS were examined.”

“Utilization of p-aminobenzoic acid as an oxidizable substrate by a Flavobacterium4 is competitively inhibited by p-aminosalicylic acid5 , and it has been suggested that p-aminosalicylic acid competes with the substrate for the specific transport mechanism(s)6.”

“Of the three compounds previously reported to be antagonistic, only p-aminosalicylic acid influenced the oxidative dissimilation of p-aminobenzoic acid7.”