2-Hydroxy-3-methylbutyric acid (2-hydroxyisovaleric acid) is a metabolite found in the urine of patients with phenylketonuria methylmalonic acidemia propionic acidemia 3-ketothiolase deficiency isovaleric acidemia 3-methylcrotonylglycemia 3-hydroxy-3-methylglutaric acidemia multiple carboxylase deficiency glutaric aciduria ornithine transcarbamylase deficiency glyceroluria tyrosinemia type I galactosemia and maple syrup urine disease.

Allomatrine is a natural product from Sophora alopecuroides L. Allomatrine when given i.c.v. may stimulate the descending dynorphinergic neuron resulting in the stimulation of KORs in the spinal cord.

dCeMM2 is a glue degrader. dCeMM2 prompts an interaction of CDK12-cyclin K with a CRL4B ligase complex, leading to the ubiquitination and degradation of cyclin K.