Stability Of Carboxypeptidase Research Articles

The interaction of xylitol with carboxypeptidase A: The influence of xylitol on enzyme structure and activity

The influence of xylitol on the conformational stability, structure, and activity of bovine pancreas carboxypeptidase A was evaluated with UV–Vis spectroscopy, spectrofluorimetry, circular dichroism (CD), and kinetic studies, as well as molecular docking. It was discovered that xylitol suppressed carboxypeptidase A's intrinsic fluorescence in the static mode by monitoring the fluorescence peaks at two temperatures (308 and 318 K). Furthermore, calculations of thermodynamic parameters revealed that the xylitol binds spontaneously to carboxypeptidase A, and van der Waals' interaction with hydrogen bonds play an essential role in the stabilization of carboxypeptidase A. The molecular docking calculations confirmed quenching fluorescence results. Furthermore, CD spectrums and fluorescence data suggested that xylitol affected the structure of carboxypeptidase A. The melting temperature (Tm) for carboxypeptidase A increased as the xylitol concentration increased, following the thermal stability tests for carboxypeptidase A xylitol complex. Furthermore, kinetic investigations revealed that xylitol raised the Vmax and kcat/Km values, implying that xylitol treated carboxypeptidase A is more stable and active than free enzyme.

The effect of sorbitol on the structure and activity of carboxypeptidase A: Insights from a spectroscopic and computational approach

In this research, the effect of sorbitol on the structure, thermal stability and activity of native carboxypeptidase A from bovine pancreas was investigated using ultraviolet–visible (UV–Vis) spectroscopy, spectroflorimertry, circular dichroism (CD) and kinetic techniques, molecular docking and simulation. The results of the measurement of fluorescence at two temperatures (308 and 318 K) showed that sorbitol quenched the intrinsic fluorescence of carboxypeptidase A with the static mode. Further, based on the calculation of some thermodynamic parameters including Gibbs free-energy, enthalpy and entropy changes, the binding process of sorbitol to carboxypeptidase A was spontaneous and the main force in stabilizing the complex consisted of the van der Waals and hydrogen interactions. The molecular docking results were also the same as those obtained for quenching fluorescence. Further, the CD spectra and fluorescence results revealed that sorbitol influenced the carboxypeptidase A structure. The thermal stability studies of the carboxypeptidase A–sorbitol complex also showed that the transition temperature (Tm) of carboxypeptidase A was increased with the raising concentration of sorbitol. In addition, the results of kinetic studies showed that sorbitol increased the Vmax and kcat/Km values, so it could increase the activity and stability of carboxypeptidase A.

Activity and Stability of Carboxypeptidase R of Experimental Small Animals

Activity and Stability of Carboxypeptidase R of Experimental Small Animals

Carboxypeptidase Y stability.

The stability of carboxypeptidase Y under different reaction conditions and in the presence various cosolvents was investigated. Loss of both hydrolysis and transpeptidation activities was monitored. Incubation of the enzyme at high temperatures or high pH resulted in the loss of both activities at the same rate. Addition of ammonium sulfate resulted in loss of transpeptidation activity but not hydrolysis activity. Addition of some organic solvents or Triton X-100 to the incubation mixture resulted in loss of both activities with transpeptidation being lost more rapidly than hydrolysis activity, while other organic solvents were observed to eliminate both activities entirely. Incubation of the enzyme in the presence of sodium dodecyl sulfate resulted in a decrease in both activities but hydrolysis was lost more rapidly than the transpeptidase activity. Implications of the observed preferential loss of activities to the labeling of peptides and proteins is discussed.