How Can Quantum Chemical Calculations Contribute to the Elucidation of Chemical Reactions? Some Theory and Examples.

extraction and acetylation of purified trypsin from bovin pancreas and study of some its physico-chemical properties

آنزیم تریپسین در شرایط قلیایی ناپایدار می باشد .و فعالیت پروتئولیتیکی تریپسین منجربه خود هضمی آن در جایگاههای خاصی می گردد. بنابر این آنزیمی با ناپایداری بالا محسوب میگردد. در سالهای اخیر موفق شدند که با ایجاد تغیرات شیمیایی با اضافه کردن فلزات خاص ، کلسیم و یا عمل استیلاسیون منجر به افزایش پایداری آنزیم تریپسین گردند. مطالعات در حال حاضر نشان می دهد که تریپسین استیله شده فعالیت آنزیمی خود را ...

High-Level Quantum Chemical Calculations of Ozone-Water Complexes

The structural and energetic characteristics of O3–H2O complexes have been investigated by means of B3LYP, MP2, MP4(SDTQ), CCSD(T) and QCISD(T) methods in conjunction with the AUG-cc-pVDZ and AUG-cc-pVTZ basis sets. Six conformers were found for the O3–H2O complex. Two different intermolecular interactions were expected to participate in the formation of complexes, namely conventional O∙∙∙H hyd...

[Analysis of enzymatic reactions by quantum chemical calculations].

Density functional theory (DFT) is now extensively used as a research tool for the investigation of structure and reactivity of biological systems; however, its high computational demands still restrict the applicability of DFT to systems of a few tens up to one hundred atoms. A combined quantum mechanical/molecular mechanical (QM/MM) approach is applicable as an important method to study whole...

The Representation of the Chemical Bond in Quantum Chemical Calculations

The mathematical representation of chemical bonds in molecules is discussed. The molecule is viewed as a system of weakly interacting chemical bonds. The intrabond problems and the averaged electrostatic interbond interactions are handled at the . zeroth order, while the small interbond delocalization and dispersion effects are taken into account on the basis of the perturbation theory. A speci...

How Political Science Can Contribute to Public Health: A Response to Gagnon and Colleagues