amino acids

  1. M

    Amino Acids (e.g. Tyrosine) and their charge

    I recently checked out a document from UCLA a which shows the pKa's of each amino acid. I know that each protein's environment can have a affect on pKa's, or so I was told, but that is besides the point. My question is in regards to figuring out charge, specifically for tyrosine. Assumptions...
  2. esob

    Enzyme binding environments

    I'm a little confused on binding sites in general, since we never went into that much detail in elementary biochem. I have watched all the KA videos and done the EK review but am still a bit hazy. Do hydrophobic binding sites on enzymes mean that they will interact preferably with hydrophobic...
  3. O-Block Uchiha

    Last Minute Amino Acid Help

    Hello all, my MCAT is this Thursday and I'm feeling good. One thing still befuddles me a lil. So when we're looking at an AAs charge in solution, are we looking at the pka or pI? Take Asparatate for example, it's pI is roughly 2.7 and it's pka is 4, so if a solution had a pH of 3, would it be...
  4. rabbott1971

    Charges on Peptides

    I am trying to count charges and don't get this to add up. H,R,K each give +1, and D,E each give -1. Is there more to it than this? I thought option C resulted in +3 -3 = 0, but the solution says it is net -1.
  5. sera2018

    Defective enzyme retaining some function but not all

    I was doing an MCAT diagnostic test from kaplan. One of the topics was a mutation that caused an enzyme to lose only some of its function but retained most. I'm confused in general how an enzyme can only lose some part of its function but not all of it. Doesn't losing some function indicate...
  6. A

    MCAT EK Question on Peptide Bond Formation

    Seeing as there's no one else who commented on this, I'm assuming I'm wrong about something. On page 12 in the Examkracker's BIO1 manual (topic is Amino Acids and Proteins), there is a statement that "nitrogen is most stable with four bonds". The statement is in reference to the partial double...
  7. B

    Cysteine is Polar or Nonpolar?

    Kaplan considers Cysteine to be polar while I have read in my Cell Bio book that cysteine is nonpolar. Does anybody know what AAMC considers Cysteine to be classified under? Which brings me to my next question. When 2 cysteines come together to form a disulfide linkage, why do they form a...