The mechanism of amantadine acetylation
Bibliographic record
Abstract
Amantadine is an irnportant drug in the treatment of and prophylaxis against influenza A virus infection anci in the treatment of Parkinson's disease.Amantadine was approved for the preceding diseases in the late 1960s and was initially reported not to be subject to metabolism.However, in 1985, N-acetylation was identif,red as a minor metabolic pathway for amantadine.No further study in this area was conducted.Therefore the mechanism that rnediates the acetylation of amantadine remained to be described.This thesis work has investigated how amantadine is acetylated.The hypotheses of this project were divided into two parts: 1.The N-acetyltransferases, NATI and NAT2, do not catalyze the acetylation of amantadine; 2. The enzyme, spermidine/spermine Nr- acetyltransferase (SSAT), that catalyzes the acetylation of spermidine and spermine is responsible for catalyzing the acetylation of amantadine when this enzlnne is induced or overexpressed.The first srudy used NATI and NAT2 enzymes from three different sources, rat liver, rabbit liver, and human recombinant wild type NATI and NAT2, incubated with their selective substrates p-aminobenzoic acid (PABA) and sulfamethazine (SMZ), respectively.The addition of amantadine to the selective subtrates in the same incubation medium did not inhibit their acetylation.Amantadine incubated in the absence of the substrates also was notacetylated.These results suggested that neither NAT I nor NAT2 were responsible for amantadine acetylation.The second study involved transgenic mice overexpressing SSAT and injected with amantadine.All mice excreted acetylamantadine in their urine.Controls of the same strain not overexpressing SSAT did not excrete acetylamantadine.In vitro experiments using the cytosolic liver fraction as the source of SSAT demonstrated that amantadine V could inliibit spermidine acetylation competitively.Incubation of amantadine with an acetyl-coenzynte A. regenerating system and transgenic mouse liver as the cytosolic source of SSAT produced modest amounts of acetylamantadine.Co-incubation of amantadine and the NAT2 selective substrate SMZ inhibited production of acetylamantadine.The selective NAT2 substrate, SMZ, but not the NATI-selective substrate PABA, modestly inhibited spermidine acetylation.In conclusion, the data support the hypothesis that amantadine acetylation is catalyzed by SSAT and may be a specific substrate for this enzyme.These frndings indicate that SSAT may be a drug acetylation pathway when induced or overexpressed and may contribute to NAT2 selective substrate acetylation. VI ACKNOWLEDGBiVIENTSFirst of all I would like to express my sincere thanks to Dr. Daniel Sitar for providing me the opportunity to pursue a scientific carrier.As a supervisor, he offered excellent mentorship, guidance, and shared his insights into doing science.I greatly appreciated his generous availability of time to discuss the project and all its complexities.His enthusiasm for science always amazed me and provided the motivation to continue the pursuit of scientific insight.As a friend, he appreciated some of the hurdles that I faced in everyday life and always tried to help if he could, and these gestures will never be forgotten.The Department of Pharmacology and Therapeutics as a whole provided a great atmosphere for learning and personal development.All professors are praise wortliy in their generous availability of time for the students when they require it.Time is the greatest gift a professor can give a sfudent and I greatly appreciated all the discussions that I had with different professors.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".