Antibody-carboxypeptidase A Conjugate

As a leading company in the field of antibody development, Creative Biolabs has developed comprehensive antibody-directed enzyme prodrug therapy (ADEPT) technology platform. Particularly, we offer customized antibody-carboxypeptidase A conjugate services for customers with optimized enzyme and antibody conjugation strategies.

Carboxypeptidase A

Carboxypeptidase A, commonly known as the pancreatic exopeptidase, can hydrolyze peptide bonds of C-terminal residues with aliphatic or side-chains aromatic. Currently, this enzyme is referred to CPA1. Another related pancreatic carboxypeptidase is referred to CPA2. In addition, there are four other types mammalian enzymes, namely CPA-3 to CPA-6. Carboxypeptidase A is synthesized in pancreas and is critical to many processes in the human body, including post-translational modification of proteins, digestion, reproduction, and blood clotting. This single protein with such wide range functionality makes it an ideal model for research concerning other zinc proteases of unknown structure.

The molecular model of the unbound carboxypeptidase A enzyme. Fig.1 The molecular model of the unbound carboxypeptidase A enzyme.

MOA of Carboxypeptidase A

Carboxypeptidase A catalyzes the hydrolytic cleavage Methotrexate peptide/alanine prodrug yielding the parent drug Methotrexate. Methotrexate has the ability to inhibit the synthesis of DNA, RNA, thymidylates, and proteins. In addition, it can competitively and irreversibly inhibit dihydrofolate reductase, an enzyme which plays a critical role in tetrahydrofolate synthesis. Dihydrofolate reductase catalyzes the conversion of dihydrofolate into the active tetrahydrofolate. Folic acid is essential for the de novo synthesis of nucleoside and thymidine, which are esential for DNA synthesis. In addition, there are some other enzymes that are indirectly affected by methotrexate, such as 5,10-methylenetetrahydrofolate reductase and methylenetetrahydrofolate dehydrogenase.

Mechanism of Carboxypeptidase A action. Fig.2 Mechanism of Carboxypeptidase A action. (Barber, 1972)

Antibody-carboxypeptidase A Conjugate

Carboxypeptidase A is a conventional enzyme used in ADEPT development. An exclusive scFv mAb, which is a kind of humanized monoclonal antibody, is prepared for ADEPT. It could target tumor cell antigen residues when a nontoxic prodrug is administered and activated by the enzyme to the toxic drug at the tumor site. The active drug can diffuse to nearby cells and lead to a local bystander effect where antigen-negative cells and tumor supportive stromal elements are destroyed. Research has suggested that the synthesis of methotrexate (MTX) prodrugs was successful and the prodrugs were confirmed no cytotoxicity. In addition, cell cycle assays indicated that tumor cells were arrested in the S phase after ADEPT treatment, and tumors were inhibited significantly in scFv/hCPA and MTX-a-Phe treated mice.

Creative Biolabs can help you develop antibody-carboxypeptidase A conjugate based on our advanced platforms and experienced scientists. We promise to complete every antibody-enzyme conjugate project in a cost-effective manner. Please contact us for more information and a detailed quote.


  1. Barber, A. K.; Fisher, J. R. A mechanism of action for carboxypeptidase A. Proceedings of the National Academy of Sciences. 1972, 69(10), 2970-2974.

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