Phenylacetylglutamine is a normal constituent of human urine but other mammals such as the dog cat rat monkey sheep and horse do not excrete this compound. Phenylacetylglutamine is a major nitrogenous metabolite that accumulates in uremia. Phenylacetylglutamine also is a microbial metabolite found in Christensenellaceae Lachnospiraceae and Ruminococcaceae.

X-press Tag is an N-terminal leader peptide; this N-terminal peptide contains a polyhistidine sequence, the Xpress epitope (part of bacteriophage T7 gene 10 protein) and an enterokinase cleavage site. Anti-Xpress antibodies recognize the Xpress epitope sequence found in this leader peptide.

Dipyrithione appears to have novel cytotoxicity and potent broad-spectrum antitumor activity.