Drawing titration curves for amino acids - strategy, intuition, and examples скачать в хорошем качестве

Drawing titration curves for amino acids - strategy, intuition, and examples

Strategy for drawing amino acid titration curves; 1. Identify # of ionizable groups at least 2(N- & C-termini), possibly 3(R) this #= # of OH⁻ equivalents (eq.) required to fully deprotonate it 2. Draw your x-axis, extending that many equivalents-worth label each 0.5 increment 3. Sketch the state of each ionizable group at each increment & label its charge remember groups will deprotonate in order of increasing pKa (most acidic first) 4. Plot points intersecting each at 1/2-way between equivalents OH⁻ (0.5, 1.5, 2.5 - if applicable)   the corresponding pH = pKa, so [HA] = [A⁻]   5. Draw a flattish"buffering zone" around this point 6. Draw points at each 1 OH⁻ (0, 1, 2, 3 (if applicable)) halfway between the the pKas on either side the steepest part of the inflection will be here one of these will be your pI Connect the dots and lines, drawing the steepest part of the inflection curves through these equivalence points 7. Label the pI (pH at 0 net charge point) will be the average of the pKa's on either side of it average of the 2 most similar pI's blog: https://bit.ly/aminoacidtitrationcurves 19:40 How to draw an amino acid titration curve for an amino acid with a non-ionizable R group (in this case glycine as an example). 30:14 How to draw an amino acid titration curve for an amino acid with a basic R group (in this case lysine as an example). 40:22 How to draw an amino acid titration curve for an amino acid with an acidic R group (in this case glutamate as an example). 49:30 Summary and note that titration curves are nice for some things, especially helping you get a sense as to what’s going on at different pH’s, but if you want to actually calculate what the pH would be or what proportion would be protonated at a given pH, for an in-between equivalents point, the Henderson-Hasselbach equation is the place to go! http://bit.ly/phbuffers YouTube:    • Henderson-Hasselbalch equation = where it ...     P.S. Huge thanks to Dr. Jeff Sigman for helping teach me his method! blog: https://bit.ly/aminoacidtitrationcurves  Much more on amino acids: http://bit.ly/allaminoacids ; YouTube:    • Amino acids - all about 'em!   More on acids, bases, & pKa calculations:   http://bit.ly/phbuffers YouTube:    • Henderson-Hasselbalch equation = where it ...   &    • Видео      more about all sorts of things: #365DaysOfScience All (with topics listed) 👉 http://bit.ly/2OllAB0 or search blog: http://thebumblingbiochemist.com