Determination of denaturation temperature of connective tissue proteins by viscometric measurements.

Viscometric denaturation temperature of connective tissue proteins was determined by measuring viscosity with a Brookfield viscometer, using a LV SC4 - 18, 25 or LV3 spindle and shear rates from 50 to 110 s-1 (Fig.1). Freeze-dried protein samples were dissolved in 0.5 M acetic acid at 4 °C and concentration of 20 mg/mL. The solution was stirred with a magnetic stirrer for 2 hours. The measurement was made in the temperature range of 5 ÷ 40 °C with temperature increase equal 0.1 °C / minute. The volume of the sample used for the determination was dependend on the used spindle. Data allowed to determine the denaturation temperature of connective tissue proteins. Fig.1. Brokfield rotational viscometer - model DV-III +.