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pKa values for acetic, chloroacetic, dichloroacetic and trichloroacetic acids. Inductive effects and mesomeric effects affect the pK a values. A simple example is provided by the effect of replacing the hydrogen atoms in acetic acid by the more electronegative chlorine atom.
In cell biology, protein kinase A (PKA) is a family of serine-threonine kinase [1] whose activity is dependent on cellular levels of cyclic AMP (cAMP). PKA is also known as cAMP-dependent protein kinase (EC 2.7.11.11). PKA has several functions in the cell, including regulation of glycogen, sugar, and lipid metabolism.
a value does in general depend on the pH value. [32] This dependence is small for weakly interacting groups like well solvated amino acid side chains on the protein surface, but can be large for strongly interacting groups like those buried in enzyme active sites or integral membrane proteins. [33] [34] [35]
In chemistry, biochemistry, and pharmacology, a dissociation constant (K D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions.
The pathway may also be deactivated downstream by directly inhibiting adenylyl cyclase or dephosphorylating the proteins phosphorylated by PKA. Molecules that inhibit the cAMP pathway include: cAMP phosphodiesterase converts cAMP into AMP by breaking the phosphodiester bond, in turn reducing the cAMP levels
The structure of the molecule of urea is O=C(−NH 2) 2.The urea molecule is planar when in a solid crystal because of sp 2 hybridization of the N orbitals. [8] [9] It is non-planar with C 2 symmetry when in the gas phase [10] or in aqueous solution, [9] with C–N–H and H–N–H bond angles that are intermediate between the trigonal planar angle of 120° and the tetrahedral angle of 109.5°.
The letter p could stand for the French puissance, German Potenz, or Danish potens, all meaning "power", or it could mean "potential". All of these words start with the letter p in French , German , and Danish , which were the languages in which Sørensen published: Carlsberg Laboratory was French-speaking; German was the dominant language of ...
The pKa of KHP is 5.4, so its pH buffering range would be 4.4 to 6.4; however, due to the presence of the second acidic group that bears the potassium ion, the first pKa also contributes to the buffering range well below pH 4.0, which is why KHP is a good choice for use as a reference standard for pH 4.00. [8] [9]