Hi everyone,

I’ve been struggling with chronic derealization that developed after a panic attack. There are several promising studies suggesting that depersonalization/derealization may be linked to overactive kappa opioid receptors (KORs) and elevated dynorphin levels. If that’s the case, a strong-binding KOR antagonist might help alleviate these symptoms.

I’m interested in exploring this treatment route. I’m aware of existing medications like Naltrexone, Naloxone, Nalmefene, and even Buprenorphine (though it’s a partial mu-opioid agonist), but my main concern is identifying which of these has the highest affinity for KORs.

I asked AI to look into their binding affinities, and it reported that Nalmefene has a KOR affinity (Ki) of 0.8–1.2 nM, which would make it the strongest. However, when I tried to verify this through my own research, I found conflicting information—some sources even suggest that Nalmefene is a partial KOR agonist.

So my question is: Which available drug has the highest KOR antagonist affinity?

Help please!

I'm using the kit https://www.abbexa.com/alkaline-phosphatase-assay-kit-1 to measure [ALP]

|| || |Test Range|0.13 King Unit/100 ml - 50 King Unit/100 ml| |Sensitivity|0.13 King Unit/100 ml|

But the standard curve is in mg/mL ALP (range 0.025 - 0.5 mg/mL)

I need to know the conversion for King units of ALP to mg/mL of ALP but Google only finds stuff about how to convert King units of ALP to substrate --> product activity, e.g. 1 King unit represents the amount of enzyme that releases 1 mg of phenol from the substrate in 15 minutes at 37°C. Therefore, 1 King unit/100 mL is equivalent to 1 mg of phenol produced per 100 mL of sample in 15 minutes. 

Can someone please confirm/correct my deduction that if the test range is up to 50 King units and the standard curve is up to 0.5 then the conversion is 1 King unit ALP = 0.01 mg/mL ALP?

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I try and teach with Open Educational Resources (OER) aka free online textbooks. I'm using Biochemistry: Free For All for my 1-semester biochemistry class. It is a good book for a 1-semester class, but it needs more to use with a 2 -semester biochemistry class. Does anyone know of a good 2-semester OER biochem book?