Substrate specificity of prostate-specific membrane antigen

Abstract

A series of putative dipeptide substrates of prostate specific membrane antigen (PSMA) was prepared that explored α-and β/γ-linked acidic residues at the P1 position and various chromophores at the P2 position, while keeping the P1' residue constant as L-Glu. Four chromophores were examined, including 4-phenylazobenzoyl, 1-pyrenebutyrl, 9-anthracenylcarboxyl-γ-aminobutyrl, and 4-nitrophenylbutyryl. When evaluating these chromophores, it was found that a substrate containing 4-phenylazobenzoyl at the P2 position was consumed most efficiently. Substitution at the P1 position with acidic residues showed that only γ-linked L-Glu and D-Glu were recognized by the enzyme, with the former being more readily proteolyzed. Lastly, binding modes of endogenous substrates and our best synthetic substrate (4-phenylazobenzoyl-Glu-γ-Glu) were proposed by computational docking studies into an X-ray crystal structure of the PSMA extracellular domain.

Structural Basis of Interactions between Human Glutamate Carboxypeptidase II and Its Substrate Analogs

“…However, the stereochemical preference of GCPII at the P1 position is clearly regioselective and likely depends on the nature/chemistry of a functionality attached to the P1 moiety (Ref. 35 and data presented here). For example, while Ac-γ-L-Glu-LGlu and Ac-γ-D-Glu-L-Glu show similar K m and k cat values, the kinetic constants for Ac-α-L-Glu-L-Glu and Ac-α-D-Glu-L-Glu exhibit significant difference, with the L-stereoisomer being clearly preferred.…”

PET Imaging in Prostate Cancer: Focus on Prostate-Specific Membrane Antigen

“…1), as well as the thiol-based GCPII inhibitors, came from research conducted at ZENECA and then Guilford Pharmaceuticals [106, 107]. Later, extensive studies with the phosphoramidate inhibitors were produced by the Berkman group [108–110]. The initial preparation and testing of urea-based inhibitors was reported by Kozikowski [111, 112].…”

GCPII Imaging and Cancer

“…The initial work on the phosphonate and phosphate inhibitors, which included the potent GCPII inhibitor 2-(phosphonomethyl) pentanedioic acid, 2-PMPA (IC50 ~ 0.9 nM, [184]), as well as the thiol based GCPII inhibitors, came from research conducted at ZENECA and then Guilford Pharmaceuticals [185, 186]. Later, extensive studies with the phosphoramidate inhibitors came from Berkman’s group (IC50s ~ 0.5–20 nM), [187–189]. The initial preparation and testing of urea-based inhibitors was reported by Kozikowski et al .…”