Different effects of l-arginine on the heat-induced unfolding and aggregation of proteins

Influence of l‐homoarginine as an analogue of l‐arginine on the heat‐induced aggregation of proteins

“…The data obtained in the experiments with l ‐homoarginine indirectly confirmed our findings on arginine published previously, i.e. at low concentration the amino acid having a guanidium group can promote the aggregation of proteins . This study reveals the different effect of arginine analogue on proteins depending on what the concentration of additive is used and what protein is investigated.…”

“…The influence of low concentration of l ‐homoarginine on hGH thermal aggregation as shown in this study as well as of arginine as previously described was different compared to both pGH and mGH. Therefore, to clarify this phenomenon, additional experiments were performed testing the influence of two other basic amino acids—histidine and lysine—on the thermal melting and structure of hGH.…”

“…Thermal unfolding of pGH was additionally studied at the concentration of 1 mg/mL. The onset temperature of aggregation was determined as previously described …”

“…If protein unfolding is concomitant with its aggregation, onset temperatures of melting and aggregation are better parameters . Thus, the formation of protein aggregates was monitored by the changes of high tension voltage applied to the photomultiplier tube of detector of CD spectrometer, and the onset temperature of aggregation was chosen as the best parameter to characterize the effect of arginine on the proteins . We found that the onset temperature of aggregation of both porcine growth hormones (pGH) and mink growth hormones (mGH) increased with increasing arginine concentration.…”

Thermal Denaturation and Aggregation Assays in Analytical Biochemistry

“…In such experiments thermal denaturation is studied in the regime of heating of the protein solution at a constant rate. To control unfolding of the protein molecules, different physical methods are used, such as Differential Scanning Calorimetry (DSC) [1][2][3][4][5][6][7][8][9], intrinsic fluorescence [7,9,[10][11][12][13], extrinsic fluorescence based on the measurements of the emission from extrinsic fluorescent dyes (8-anilino-1-napthalenesulfonic acid, 4,4′-bis(1-anilino-8naphthalenesulfonic acid), SYPRO Orange, Nile red) [14][15][16][17][18][19][20][21][22][23][24][25][26][27] and circular dichroism [10,[28][29][30]. When denaturation of the protein is accompanied by irreversible aggregation of denatured protein molecules, the denaturation process can be followed by monitoring the increase in the light scattering of the protein solution [10,20,[31][32][33][34][35][36] or the increase in apparent absorbance in the visible region [7,11,…”