Comparison of Heat-Induced Aggregation of Globular Proteins

Abstract

Typically, heat-induced aggregation of proteins is studied using a single protein under various conditions (e.g., temperature). Because different studies use different conditions and methods, a mechanistic relationship between molecular properties and the aggregation behavior of proteins has not been identified. Therefore, this study investigates the kinetics of heat-induced aggregation and the size/density of formed aggregates for three different proteins (ovalbumin, β-lactoglobulin, and patatin) under various conditions (pH, ionic strength, concentration, and temperature). The aggregation rate of β-lactoglobulin was slower (>10 times) than that of ovalbumin and patatin. Moreover, the conditions (pH, ionic strength, and concentration) affected the aggregation kinetics of β-lactoglobulin more strongly than for ovalbumin and patatin. In contrast to the kinetics, for all proteins the aggregate size/density increased with decreasing electrostatic repulsion. By comparing these proteins under these conditions, it became clear that the aggregation behavior cannot easily be correlated to the molecular properties (e.g., charge and exposed hydrophobicity).

Aggregation and Conformational Changes in Native and Thermally Treated Polyphenol Oxidase From Apple Juice (Malus domestica)

“…Therefore, a sequence of fractional blue shifts was noticed with increasing temperature, and the fall in PPO fluorescent intensity induced by thermal processing was prominent; this result was in agreement with fluorescence spectrum changes of thermally processed PPO induced by disruption of its tertiary structure (Zhou et al, 2016 ). Hydrophobic interaction of a few unfolding particles may overcome the electrostatic obstacle for protein aggregation and consequently form aggregates (Delahaije et al, 2015 ). Compared with untreated PPO (18.42 ± 0.60), the lowest relative activity of 12.72 ± 0.09 was observed with thermally treated purified PPO (Table 1 ).…”

Design of β-lactoglobulin micro- and nanostructures by controlling gelation through physical variables

“…Thermally induced gelation usually consists in the unfolding of polypeptide chains of protein in native state with concomitant exposure of initially buried hydrophobic amino acid residues, and subsequent self-aggregation of protein molecules through physical (electrostatic and hydrophobic) and chemical (disulphide) interactions (Delahaije, Wierenga, Giuseppin, & Gruppen, 2015;Teng, Xu, & Wang, 2015). The extent and behavior of protein aggregation depends on several physical conditions such as heating temperature, time of heating, pH, protein concentration and ionic strength , and can result in different structures with various sizes, shapes, morphologies and charges.…”

“…Fan et al (2019) studied the influences of mannosylerythritol lipid-A at concentration ranging from 0 to 5.0 mg mL −1 on the structure formation and functional properties β-Lg aggregates at fixed β-Lg concentration (2.0 %), temperature (85°C), and pH (5.8) conditions. Delahaije et al (2015) investigated the kinetics of heat-induced aggregation and the size/density of β-Lg under various pH (5, 6 and 7), ionic strengths (10, 40 and 90 mmol L -1 of NaCl) and protein concentrations (1, 2, 5 and 10 g L −1 ); these conditions were, however, tested isolated. Perez, Andermatten, Rubiolo, and Santiago (2014) studied the impact of a narrow pH range (6.5, 7.0 and 7.5) and temperature of heating (15,30,45 and 60 min) on the development of β-Lg aggregates as carriers systems, at fixed protein concentration (1.0 %) and heating temperature (85°C) conditions.…”

Dissociative mechanism for irreversible thermal denaturation of oligomeric proteins

“…To calculate the n value, the series of kinetic curves of inactivation at various initial protein concentrations should be obtained. The order of inactivation with respect to the protein is a power coefficient in the expression connecting the initial rate of inactivation (v 0 ) and the initial protein concentration C 0 (Borzova et al 2015;Curto et al 2012;Delahaije et al 2015;Eronina et al 2016;Kurganov 2013aKurganov , b, 2015Kurganov , 2016Le Bon et al 1999;Roefs and De Kruif 1994;van Boekel 2009):…”