Hydroxymethyl cimetidine

Formula : C10-H16-N6-O-S
CAS : 59359-50-1 

Blood metabolite of cimetidine.

Hydroxymethylbilane

Formula :
CAS : 71861-60-4 

Tetrapyrrole intermediate in pigment biosynthesis by Euglena gracilis; universal intermediate in biosynthesis of uroporphyrinogen III.

Hydroxymethylbilane Synthase

Formula :
CAS : 9036-47-9 

An enzyme that catalyzes the tetrapolymerization of the monopyrrole PORPHOBILINOGEN into the hydroxymethylbilane preuroporphyrinogen (UROPORPHYRINOGENS) in several discrete steps. It is the third enzyme in the 8-enzyme biosynthetic pathway of HEME. In humans, deficiency in this enzyme encoded by HMBS (or PBGD) gene results in a form of neurological porphyria (PORPHYRIA, ACUTE INTERMITTENT). This enzyme was formerly listed as EC 4.3.1.8.