Why and when is lysine charged - Chemistry Stack Exchange
2015年2月6日 · Depending on the source, Lysine is usually stated as a charged amino acid with a $\ce{NH3+}$ group. However the video I'm watching is calculating the charge at 5 pH and it writes Lysine out with $\ce{NH2}$ and goes on to say that because the solution is pH 5, then $\ce{NH2 -> NH3+}$ and arguments that THIS is why Lysine is charged.
biochemistry - How can I properly calculate the isoelectric point …
2020年7月18日 · The following amino acid is called lysine. I was asked to calculate its isoelectric point, with the given $\mathrm pK_\mathrm a$ values. I've searched a lot, and the most helpful post that I found was How do I calculate the isoelectric point of amino acids with more than two pKa's? According to orthocresol's answer:
Why is the lysine side chain more basic? - Chemistry Stack Exchange
2024年1月15日 · This is clearly observed in a comparison of the ammonium group pKa on glycine (~9.8) vs methylamine (~ 10.7). This effect is much stronger for the a-amino group of lysine vs the e-amino group, whose pKa is close to what is typical for an alkyl amine $\endgroup$ –
physical chemistry - Calculating charge on amino acid from pKa ...
2013年11月27日 · For this, you can use the Henderson-Hasselbalch equation.Using the degree of dissociation, $\alpha$, this can be written as $$\mathrm{pH} = \mathrm{p}K_\mathrm{a} + \log\frac{\alpha}{1- \alpha}$$ Rewriting to solve for $\alpha$: $$\alpha = \frac{1}{10^{\mathrm{p}K_\mathrm{a} - \mathrm{pH}} + 1}$$ As stated above, $\alpha$ is the …
What is the charge of the amino acid lysine at pH 2?
2018年3月16日 · The table you cite is for proteins. When lysine gets incorporated into a protein, it forms peptide bonds with its carboxylate and its main chain amino function groups. Therefor, these groups no longer exist and don't get protonated or deprotonated (unless the lysine is the C-terminus or the N-terminus, in which case the table gives the wrong ...
How do "basic" amino acids (lysine, arginine) act as base under ...
2020年4月10日 · Histidine is a common acid/base catalyst. Its pKa is close to 7, so an appreciable fraction is protonated and an appreciable fraction is deprotonated. Often, this amino acid will act as acid and as base in different steps of the same mechanism (e.g. RNase). Lysine. Lysine is not a typical acid base catalyst.
acid base - Why is the side chain of lysine more basic? - Chemistry ...
2021年1月22日 · $\begingroup$ @MaxW The pKa on Wikipedia is 4.88, which is less acidic than the COOH on lysine. Is this because of the alpha NH3+ stabilizing the conjugate base? What does this have to do with the acidity of the two amines? $\endgroup$ –
What is the pI of lysine tripeptide? - Chemistry Stack Exchange
2021年6月30日 · Applying Henderson–Hasselbalch equation to amino acids: which pKa to use to calculate Z-/HZ ratio? 3 Identifying unknown solution with indicators. why is one pKa value ignored and how to treat negatives values?
pKaH of pyridine versus other imines - Chemistry Stack Exchange
I have been trying to find the original data for the statement that the cyclic imine (or rather its conjugate acid) has a pKa of around 9. Typically, imines have a pKa between 5 and 7, so this seems unusually high for a start. If this number is wrong then it means that pyridine may have quite a typical pKa for a cyclic imine of this type.
biochemistry - How do I calculate the isoelectric point of amino …
2016年7月28日 · This procedure can of course be extended to the amino acids with acidic side chains (aspartic acid; glutamic acid) and those with basic side chains (lysine; arginine; histidine). Share Cite