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BabcockHall

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Everything posted by BabcockHall

  1. It is possible to estimate the pI of any protein of known sequence. Just import the sequence into a pI calculation routine, such as the one at ExPASy.
  2. Your terminology is a bit unusual. A progress curve describes the rate of consumption of substrate or the appearance of product over time. A standard curve is sometimes created by making measurements of rate while varying the concentration of enzyme. Is this a homework problem or is this a research problem?
  3. Two component systems are found in the archaea. Most of the two component systems with which I am familiar are in bacteria, and they are often transcriptional activators.
  4. With respect to your first question, do you have any thoughts on what might happen? With respect to your second question, decanoate is somewhat longer, making it more hydrophobic I suppose. Do you have a particular reason for asking?
  5. Gas-phase acidities are obviously measured in the complete absence of solvent (my recollection is that mass spectrometry is involved, but I don't recall any details). Many pKa values are measured in water, but many others are tabulated in DMSO. With respect to primary, secondary, and tertiary amines, the relative order of pKa values is affected by how well the conjugate acid (which is a cation) is solvated by water, as well as electronic effects that are intrinsic to the cation.
  6. Did you try doing a search such as: chloroform methanol?
  7. One thing to be aware of in comparing the basicities of ammonia and gradually more methyl-substituted amines is that one has to specify gas-phase versus in solution. The order of basicities is different.
  8. What experiment could you use to judge cross-reactivity?
  9. Can you define "initial rate" for us?
  10. PBr3 is another way to convert an alcohol into a alkyl bromide.
  11. For starters, I suspect that one needs to specify whether we are discussing the iron with or without the oxygen molecule present. I remember looking into this one time and deciding that the answer might be more complicated than I thought it was because not all six ligands are identical.
  12. "Chloroxylenol (4-chloro-3,5-dimethylphenol; p -chloro- m -xylenol) is the key halophenol used in antiseptic or disinfectant formulations (66). Chloroxylenol is bactericidal, but P. aeruginosa and many molds are highly resistant (66, 432). Surprisingly, its mechanism of action has been little studied despite its widespread use over many years. Because of its phenolic nature, it would be expected to have an effect on microbial membranes." I found this in a review: Clin. Microbiol. Rev. January 1999 vol. 12 no. 1 147-1791 January 1999
  13. What are the boiling points of water versus glycerol?
  14. As a general rule when I freeze a protein, I try to freeze it quickly. I would imagine that some of the same considerations apply to freezing DNA.
  15. I am not a PCR person; therefore, I will keep my response very general. One unit of any enzyme is the amount of enzyme needed to convert one micromole of substrate to product under defined conditions. It is an extensive property, and it is proportional to the number of moles or to the mass of an enzyme. The volume of TAQ polymerase to which this responds depends on the number of units per µL (this number is related to the specific activity of the polymerase, in units per milligram of protein). It might vary slightly from one lot of enzyme to the next.
  16. The lock keeps the field from drifting by examining the signal from the deuterium in the solvent.. Shimming makes the field more homogeneous using small changes in the magnetic field along certain axes, such as the z axis. Tune means the same thing as tuning your radio (improved S/N). Gain refers to how much amplification a signal receives. I suggest a good book like Fukushima and Roeder's "The Nuts and Bolts of NMR."
  17. Can you obtain the DNA for each enzyme?
  18. We don't dump answers at this site. Please show your work before we attempt to help you.
  19. For the dissolution of KCl, deltaS = +314. For the dissolution of CaSO4, deltaS = -569. I don't seem to have a reference handy. But the difference is likely related to the greater charges needing more waters of salvation.
  20. Do you have to perform the study by sequencing proteins, or for your purposes is sequencing the DNA just as good? IIUC the latter is far cheaper and more automated.
  21. Each salt must be decided on a case-by-case basis, and the change in entropy of the solvent cannot be ignored. The entropy change for the dissolution of KCl is a positive number. The entropy change for the dissolution of calcium sulfate is a negative number.
  22. I read this question differently from Xalatan. IMO if the polymerase moves right to left, it will treat the top strand as the template strand.
  23. What chemical properties does the anion in (1) possess? The starting material is an epoxide. What do you know about epoxides?
  24. I would ask whether any subsequent reaction might remove the deuterium label. You will probably have to examine the chemical mechanisms by which these enzymes work, starting with triosephosphate isomerase and aldolase.
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