Proteolytic activity of an antibody light chain.
Journal of immunology (Baltimore, Md. : 1950)
confidence
Key findings
Antibody light chain hydrolyzed VIP; heavy chain and irrelevant L chain inactive; H chain modulated catalytic activity. No clinical/biological endpoints.
View source on PubMed (PMID 7963569) ↗
- Sample size
- Not reported
- Population
- In vitro antibody light chain study
- Dosing
- Not reported
- Duration
- Not reported
- Route
- In vitro
- Blinding
- not_reported
- Controls
- irrelevant light chain, heavy chain alone
- Drug class
- neuropeptide
Full abstract
The light chain (L chain) of a mAb raised against unactivated vasoactive intestinal peptide (VIP) hydrolyzed this peptide, whereas the heavy chain (H chain) and an irrelevant L chain were without activity. The reaction kinetics were consistent with efficient substrate recognition by the anti-VIP L chain compared with conventional proteases. The L chain cleaved four peptide bonds clustered between residues 16 and 21 in VIP. Mixtures of the L chain with its H chain partner displayed reduced hydrolytic activity compared with the free L chain, suggesting that the H chain is a modulator of the catalytic activity. These observations suggest: 1) the immune system can generate catalytic sites in the L chain subunit of Abs found in response to polypeptide Ags, and 2) free L chains found in vivo could display an Ag-specific catalytic function.