Sucrase (from yeast)

Obesity and type 2 diabetes mellitus (T2DM) are major health concerns worldwide, often managed with treatments that have significant limitations and side effects. This study examines the potential of sodium alginates, extracted from Ecklonia radiata and Sargassum elegans, to inhibit digestive enzymes involved in managing these conditions. We chemically characterized the sodium alginates and confirmed their structural integrity using FTIR, NMR, and TGA. The focus was on evaluating their ability to inhibit key digestive enzymes relevant to T2DM (α-amylase, α-glucosidase, sucrase, maltase) and obesity (pancreatic lipase). Enzyme inhibition assays revealed that these sodium alginates moderately inhibit α-glucosidase, maltase, and lipase by up to 43%, while showing limited effects on sucrase and α-amylase. In addition, the sodium alginates did not affect glucose uptake in human colorectal cells (HCT116), indicating they do not impact cellular glucose absorption. In summary, while the observed enzyme inhibition was moderate, the targeted inhibition of α-glucosidase, maltase, and lipase suggests that sodium alginates could be beneficial for managing postprandial hyperglycemia and lipid absorption in the context of T2DM and obesity.

Experimental data show that the effect of temperature on enzymes cannot be adequately explained in terms of a two-state model based on increases in activity and denaturation. The Equilibrium Model provides a quantitative explanation of enzyme thermal behaviour under reaction conditions by introducing an inactive (but not denatured) intermediate in rapid equilibrium with the active form. The temperature midpoint (T_eq) of the rapid equilibration between the two forms is related to the growth temperature of the organism, and the enthalpy of the equilibrium (ΔH_eq) to its ability to function over various temperature ranges. In the present study, we show that the difference between the active and inactive forms is at the enzyme active site. The results reveal an apparently universal mechanism, independent of enzyme reaction or structure, based at or near the active site, by which enzymes lose activity as temperature rises, as opposed to denaturation which is global. Results show that activity losses below T_eq) may lead to significant errors in the determination of ΔG*_cat made on the basis of the two-state (‘Classical’) model, and the measured kcat will then not be a true indication of an enzyme's catalytic power. Overall, the results provide a molecular rationale for observations that the active site tends to be more flexible than the enzyme as a whole, and that activity losses precede denaturation, and provide a general explanation in molecular terms for the effect of temperature on enzyme activity.