9.B.229.1.8
FolH1 or prostate-specific membrane antigen (PSMA) of 750 aas and 1 N-terminal TMS, and possibly 1 C-terminal  TMS as well.  It has both folate hydrolase and N-acetylated-alpha-linked-acidic dipeptidase (NAALADase) activity with a preference for tri-alpha-glutamate peptides. It exhibits a dipeptidyl-peptidase IV type activity. In the intestine, it is required for the uptake of folate. In the brain, it modulates excitatory neurotransmission through the hydrolysis of the neuropeptide, N-acylaspartylglutamate (NAAG), thereby releasing glutamate. It is also involved in prostate tumor progression.  It released an unsubstituted, C-terminal glutamyl residue, typically from Ac-Asp-Glu or folylpoly-gamma-glutamates. It binds 2 Zn²⁺ ions per subunit which is required for NAALADase activity (Mesters et al. 2006). PSMA-based imaging is a promising diagnostic method for specifying the stage and detecting the low-volume progression of prostate cancer (Varga et al. 2023).