Self-association of caseinomacropeptide in presence of CaCl2 at neutral pH: Calcium binding determination. (1st May 2022)

• Record Type: Journal Article
• Authors: Loria, Karina G.; Pilosof, Ana M.R.; Farías, María E.
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 161(2022)
• Publication Date: 2022-05-01
• Subjects: Calcium binding peptides -- Calcium binding isotherms -- Self-assembly; CMP caseinomacropeptide -- DLS dynamic light scattering -- FTIR Fourier transform infrared spectroscopy -- ISE ion selective electrode -- d(H) hydrodynamic diameter; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2022.113419
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: The caseinomacropeptide (CMP) is a bioactive peptide produced during cheese making. It is found in abundance in whey. CMP aqueous solutions allow the incorporation of large amounts of CaCl2 but the mechanism of calcium-CMP interactions are unknown. In order to evaluate its calcium binding capacity, the following techniques were performed: Dynamic Light Scattering (DLS), Fourier Transform Infrared spectroscopy (FTIR), dialysis, conductivity, precipitation of CaCl2 /CMP complex by ethanol, electrochemical Ca 2+ binding isotherms, and inhibition of calcium phosphate precipitation. One mole of CMP can bind 9 mol of calcium, and the CMP self-assembles as a hexameric form. A model is proposed to explain the CMP self-association in presence of CaCl2 . Graphical abstract: Image 1 Highlights: The CMP self-assembles in presence of calcium ions as a dimer, tetramer o hexamer. One mole of caseinomacropeptide binds 1 mol of calcium ions in a high affinity site. The association constant of the high affinity site was ∼2000 L/mol. The low affinity binding sites involved 6–10 carboxylic groups of Glu, Asp and sialic acid. The association constant of the low affinity sites was ∼130 L/mol.