Exam (elaborations)
Best Biochem Notes
- Course
- Institution
The best biochemistry notes you will find. It cuts out all the crap you don't need to know and saves you time.
[Show more]
Seller
Follow
rsartorius
Reviews received
Content preview
BIOCHEMISTRY REVIEWPART I: PROTEINS
Protein Structure
In addition to the 20 common amino acids, proteins also contain derived amino acids
that are formed by post-translational modification
Peptide bonds are stable and unionized at physiological pH
The variable R-groups of peptide-bonded amino acids adopt a trans configuration
The primary structure of a polypeptide starts with the N-terminal (-amino end) on
the left-hand side and continues to the C-terminal (-carboxyl end)
The primary structure of a protein determines its functional 3 dimensional
shape
The secondary structure is stabilized predominantly by H-bonds
The alpha helix is stabilized by H-bonds between the –NH and CO groups of
amino acids 4 residues apart in the linear protein backbone
Super Secondary Structure = Leucine Zipper
The 3 dimensional tertiary structure is stabilized by a variety of weak noncovalent
bonds (ionic linkages, H-bonds, hydrophobic interactions and van der Waal’s forces)
and covalent disulfide bonds
Combinations of secondary structures found together in stable arrangements are
known as super secondary structures
Globular Proteins are tight, compact spherical macromolecules that tend to be water
soluble. They may possess a hydrophobic core of amino acids surrounded by
more polar amino acids arranged on the outer surface forming a hydrophilic layer
Fibrous proteins are insoluble in water and are composed of polypeptide chains
linked by hydrophobic interactions giving them high tensile strength and low
elasticity
Protein Characterization
In the presence of sodium dodecyl sulfate (SDS) PAGE, electrophoresis separates
proteins on the basis of size alone (SIZE)
SDS is an anionic detergent that breaks almost all noncovalent bonds, thereby
denaturing the protein and imparting a large negative charge
Using isoelectric focusing, proteins will migrate until they reach a point in the gel
where the pH is equal to their isoelectric point (pI), stopping at the point where the
net charge on the protein is zero
Molecular exclusion / gel filtration chromatography allows separation on the basis
of size and shape
A sample is passed through a column of hydrated polymer (such as Sephadex)
Large molecules cannot enter the polymer and pass quickly down the column
Small molecules enter the polymer beads, travel a greater distance and therefore
take longer to pass down the column
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller rsartorius. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.86. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
53068 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now