Validation of method for determining the isoelectric point of protein solutions

Abstract

ABSTRACT. This paper presents the validation of a method for determining the isoelectric point of collagen hydrolysates used to obtain biomaterials for medical use produced in the Collagen Department of INCDTP -Division ICPI. The advantage of the presented method is that it is easy to apply, as the Zeta potential is the key parameter controlling electrostatic interactions in particle dispersions. The technique used to measure particle movement velocity in the Malvern Zetasizer Nano instrument series is Laser Doppler Velocimetry (LDV). It is an accepted method for measuring electrophoretic mobility of particles in the solution and by calculating the Zeta potential of protein solutions through extrapolation, the isoelectric point of the protein solution is determined. KEY WORDS: biomaterials, collagen, isoelectric point, method validation VALIDAREA METODEI PENTRU DETERMINAREA PUNCTULUI IZOELECTRIC LA SOLUŢIILE PROTEICE REZUMAT. Lucrarea prezintă validarea unei metode de determinare a punctului izoelectric al hidrolizatelor de colagen folosite la obţinerea de biomateriale pentru uz medical produse în Departamentul Colagen al INCDTP -Sucursala ICPI. Metoda prezentată are avantajul că este uşor de aplicat, potenţialul Zeta fiind parametrul cheie care controlează interacţiunile electrostatice în dispersiile particulelor. Tehnica utilizată pentru măsurarea vitezei de deplasare a particulelor în seria de instrumente Malvern Zetasizer Nano este Laser Doppler Velocimetry (LDV). Este o metodă acceptată pentru măsurarea mobilităţii electroforetice a particulelor în soluţie şi din calcularea potenţialului Zeta al soluţiilor proteice prin extrapolare se determină punctul izoelectric al soluţiei proteice. CUVINTE CHEIE: biomateriale, colagen, punct izoelectric, validare metodă VALIDATION DE LA MÉTHODE POUR DÉTERMINER LE POINT ISOÉLECTRIQUE DE SOLUTIONS PROTÉIQUESRÉSUMÉ. L'article présente la validation d' une méthode de détermination du point isoélectrique des hydrolysats de collagène utilisés pour l'obtention de biomatériaux à usage médical produits dans le Département Collagène d'INCDTP -ICPI. La méthode présentée a l'avantage d'être facile à appliquer, le potentiel Zêta étant le paramètre clé qui contrôle les interactions électrostatiques dans les dispersions de particules. La technique utilisée pour mesurer la vitesse du mouvement des particules dans la série Malvern Zetasizer Nano est la vélocimétrie laser Doppler (LDV). C'est une méthode acceptée pour mesurer la mobilité électrophorétique des particules dans la solution et en calculant le potentiel Zêta des solutions protéiques par extrapolation, on détermine le point isoélectrique de la solution protéique.

Stability of enveloped and nonenveloped viruses in hydrolyzed gelatin liquid formulation

“…Briefly, samples were dissolved in buffer made of a 0.1 M Tris–HCl (pH 7.7–9.0) solution and acetate solution (pH 4.0–5.50) to make 0.25% (w/v). The zeta potential was measured, and the pH variation depending on the zeta potential was plotted and extrapolated to derive the isoelectric point at zero [ 15 ].…”

Stability of Enveloped and Nonenveloped Viruses in a Stable Gelatin Liquid Formulation

“…Brie y, samples were dissolved in buffer made of a 0.1 MTris-HCl (pH 7.7-9.0) solution and acetate solution (pH 4.0-5.50) to make 0.25% (w/v). Thezetapotential was measured,and the pH variation depending onthe zetapotential was plotted and extrapolated to derive the isoelectric point at zero [25].…”

Accurate Estimation of pKb Values for Amino Groups from Surface Electrostatic Potential (VS,min) Calculations: The Isoelectric Points of Amino Acids as a Case Study

“…As a descriptor in proteomics, it has become an important part of protein characterization and study. 31,32 Isoelectric points for peptides can be determined indirectly from physicochemical measurements, such as the ζ-potential, 33 or group contribution-based algorithms. 34−36 Combining the ansatz presented in this work with the one previously developed by our group for calculating the pK a values of carboxylic acids 25 we are able to simultaneously calculate the pK i (i = a,b) values for the acidic and basic moieties in amino acids (Figure 10).…”

“…The same principle holds true for a peptide. As a descriptor in proteomics, it has become an important part of protein characterization and study. , Isoelectric points for peptides can be determined indirectly from physicochemical measurements, such as the ζ-potential, or group contribution-based algorithms. − …”