Limited proteolysis of integrin alpha v beta3 from human placenta

• Published in: Voprosy meditsinskoi khimii Vol. 46; no. 5; p. 444
• Main Authors: Lubkova, O N, Gureeva, T A, Dilakian, E A, Solov'eva, N I, Belkin, V M
• Format: Journal Article
• Language: Russian
• Published: Russia (Federation) 01.09.2000
• Subjects: Female; Fluorescent Dyes; Humans; Hydrolysis; Oligopeptides - metabolism; Placenta - metabolism; Pregnancy; Receptors, Vitronectin - metabolism
• ISSN: 0042-8809

Purification of alpha v beta 3 integrin from human placenta with successive usage of two affinity sorbents--immobilized monoclonal antibodies to alpha v beta 3 integrin and immobilized RGD-containing decapeptide allowed to purify this integrin's partially degraded fraction, that was nevertheless able to interact with its ligand. During the incubation of partially degraded alpha v beta 3 integrin at 37 degrees C its further degradation went on. Addition of serine proteinase inhibitors: (phenylmethilsulfonyl fluoride, leupeptin and aprotinin) completely suppressed integrin further degradation of alpha v beta 3. In preparations of intact and partially degraded alpha v beta 3 integrin specific activity of two serine proteinases--urokinase and dipeptidilpeptidase IV--was discovered. alpha v beta 3 integrin, undergoing limited proteolysis, had lesser affinity towards RGD peptide, that intact integrin. The results show, that alpha v beta 3 integrin from human placenta co-purifies with serine proteinases. It is suggested that a definite part of functionally active alpha v beta 3 integrin, extracted from human placenta by triton X-100, forms a stable complex with serine proteinases.