The pKa, or acid dissociation constant, of an amino acid is strongly tied to the properties of the surrounding solvent. The hydrophobic core of a protein is a distinctly different environment than the water exposed surface of the protein and the pKa in the core is different than the normal, solvent exposed pKa. This is related to the dielectric constant, or the ease at which charge is "felt" over a distance, which is much lower in the hydrophobic core of the protein. In addition, the now fixed locations of other possibly charged amino acids nearby will also impact the pKa of the residue.
Histidine is a good amino acid to use as a buffer close to physiological pH (around 7.4) because it has a pKa near this pH value, allowing it to act as a good buffer in biological systems. At its pKa, histidine can accept or donate a proton, helping to maintain a stable pH.
The pKa of diisopropylamine is around 10-11.
The buffer pKa is important in biological systems because it determines the ability of a buffer to resist changes in pH. Buffers help maintain a stable pH environment by accepting or releasing protons to prevent drastic changes in acidity or alkalinity. A buffer with a pKa close to the desired pH of the system is most effective in maintaining stability.
The pKa of bromoacetic acid is approximately 2.64.
The pKa value of Doxofylline is approximately 4.22.
Histidine is a good amino acid to use as a buffer close to physiological pH (around 7.4) because it has a pKa near this pH value, allowing it to act as a good buffer in biological systems. At its pKa, histidine can accept or donate a proton, helping to maintain a stable pH.
Histidine can act as a versatile amino acid in enzyme active sites because of its ability to donate and accept protons over a wide pH range. This allows histidine to participate in various catalytic mechanisms, making it a common residue in enzyme active sites. Additionally, the imidazole side chain of histidine can form hydrogen bonds and coordinate with metal ions, further enhancing its role in enzyme catalysis.
The pKa of diisopropylamine is around 10-11.
The buffer pKa is important in biological systems because it determines the ability of a buffer to resist changes in pH. Buffers help maintain a stable pH environment by accepting or releasing protons to prevent drastic changes in acidity or alkalinity. A buffer with a pKa close to the desired pH of the system is most effective in maintaining stability.
The pKa of bromoacetic acid is approximately 2.64.
The pKa value of Doxofylline is approximately 4.22.
The pKa of ethanol is approximately 16.
The pKa of Triethylamine is approximately 10.75.
The pKa of drotaverine is around 8.67.
The pKa value of pyridine is 5.2.
The imidazole side chains and the relatively neutral pKa of histidine (ca 6.0) mean that relatively small shifts in cellular pH will change its charge. For this reason, this amino acid side chain finds its way into considerable use as a coordinating ligand in metalloproteins, and also as a catalytic site in certain enzymes
To calculate pKa, you can use the Henderson-Hasselbalch equation: pKa = pH + log([A−]/[HA]), where [A−] is the concentration of the conjugate base and [HA] is the concentration of the acid. Alternatively, you can look up the pKa value in a table or use a chemical database.