Let's discuss some drug allergies

The amine of the protein clearly reacts with the carbonyl C which is partially positively charged, resulting in an amide, apparently Serin and Lysin are most likely to react. The serin OH can do the same and it would result in an ester.
If you don't get the allergy you don't produce antibodies against this protein-penicillin-adduct. Their APC (antigen-presenting-cells) don't think its dangerous. or maybe the reaction is just very mild.

I think penicillin allergy is the most occurring drug allergy, but there is a lot of people who think they have an allergy against them but don't actually have an allergy against penicillin's.

10% think they have a penicillin allergy, which is totally bloated, that's all for Germany but its more like 2.5% instead of 10%
LOL. that's the same in the US: "Approximately 10% of all U.S. patients report having an allergic reaction to a penicillin class antibiotic in their past. 10% of the population reports a penicillin allergy but <1% of the whole population is truly allergic."
How that active metabolite (sulfen amide) reacts with the protein H+/K+-ATPase is an example for a disulfid-bridge.

Its quite fascinating, the sulfenamide is so reactive, it would react with any protein.
So it needs to be generated from the omeprazole exactly where its needed. and because acid is needed to generate it, you can not "overdose" on omeprazole.

The sulfenamide is only generated exact where the proton pumps are. in the canaliculi of the parietal cells.
Try to tell me how omeprazole reaches the acting site

1.mouth --omeprazole
2. stomach --omeprazole (CAVE: why are omeprazole tablets coated ??)
3. small intestine --omeprazole
4.blood stream --still omeprazole
5. parietal cell --still omeprazole
6. stomach again, but specifically in the canaliculi of the parietal cells --sulfenamide form.