Journal: Gels

Article Title: Origin of the High Variability in Sol–Gel Phase Transitions: The Agar Gelation Model

doi: 10.3390/gels12040304

Figure Lengend Snippet: ( a ) Kinetic profiles of the cold-induced reversible gelation of 0.25% agar at 25 °C (absorbance changes at 350 nm plotted vs. time) and their corresponding fitted curves (continuous line, ―). According to Equation (3), the fitting parameters of agar are A = 0.132, B = 12.087, C = 1.731, m = 0.00044, and q = −0.009. Derived kinetical parameters for agar gelation are Abs Max = 0.132, V Max = 0.007 Abs/min, t VMax = 5.9 min, and t AbsMax/2 = 11.9 min. Considering the crucial timings t 0 , t lag , t VMax , t AbsMax/2 and t AbsMax , five phases can be identified: I (lag phase), IIa (increase up to maximum rate), IIb (approximately constant-rate increase), IIIa (decelerating increase), and IIIb (plateau with a slight asymptotic drift); see main text for further details; ( b ) Kinetic profiles of the enzymatic assay of 8 μM S–2238 catalyzed by 0.15 nM human alpha thrombin at 25 °C (absorbance changes at 405 nm plotted vs. time) and their corresponding fitted curves (continuous line, ―). According to Equation (3), the fitting parameters for S–2238 are A = 0.139, B = 15.048, C = 1.742, m = −0.000027, and q = 0.005. Derived kinetical parameters for S–2238 enzymatic assay are Abs Max = 0.136, V Max = 0.006 Abs/min, t VMax = 7.2 min, and t AbsMax/2 = 14.9 min. Contrariwise, for the enzymatic reaction only IIa, IIb, IIIa and IIIb phases can be distinguished.

Article Snippet: Human alpha thrombin was purchased by Enzyme Research Laboratories (South Bend, IN, USA).

Techniques: Derivative Assay, Enzymatic Assay