Chapter 3 (part 2) - Chapter 3 (part 2) Protein...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 3 (part 2) Protein purification and Analysis N CH C CH 3 N O CH C H O O H 3 N CH C CH 2 O CH 2 S CH 3 H H Review: Protein Nomenclature Met-Ala-Gly 1. The order of amino acids in a protein is known as the proteins sequence = primary structure. 2. Each amino acid in the sequence is called a residue. 3. Amide bond links the amino acids is called a peptide bond. 4. To name the amino acids,, ine or ate ending is changed to yl Alanine becomes alanyl, glutamate becomes glutamyl, etc. Because carboxyl group is changed to an acyl group. Except for asparagine, glutamine, and cysteine where e ending is changed to yl (cysteine becomes cysteinyl). C-terminus is not changed since it still has a carboxyl (glycine residue is still called glycine in peptide above). 5. Naming from N-terminus to C-terminus corresponds to direction of protein synthesis biologically. N CH C CH 3 N O CH C H O O H 3 N CH C CH 2 O CH 2 S CH 3 H H N-terminus and C-terminus still carry a charge (+ and -), but other amino acid residues a- amino and a-carboxyl groups do not carry a charge since they are now in an amide bond. Side chains of the internal residues can still carry a charge. Solubility of a protein largely depends on these amino acid side chains. Side chain interactions with each other leads to 3-dimensional shape of a protein and its stability (secondary and tertiary structure, which will be examined in the next chapter). • is a unique characteristic of every protein • is encoded by the nucleotide sequence of DNA • is thus a form of genetic information • is read from the amino terminus to the carboxyl terminus The Sequence of Amino Acids in a Protein The sequence of ribonuclease A Insulin consists of two polypeptide chains, A and B, held together by two disulfide bonds. The A chain has 21 residues and the B chain has 30 residues. The sequence shown is that of bovine insulin. Other points that I haven’t mentioned yet… Class of Protein Example Function Structural collagen, keratin strengthen tendons skin, hair, nails Enzymes DNA polymerase replicates and repairs DNA Transport proteins hemoglobin transports O 2 to cells Contractile proteins actin, myosin cause contraction of muscles Protective proteins antibodies complex with foreign particles Hormones insulin regulates glucose metabolism Toxins snake venoms incapacitate prey Proteins that provide all of the essential amino acids in about the right proportions for humans are termed complete proteins. Examples of complete proteins are those found in meat, fish, milk and eggs. About 50 g of complete protein per day is adequate for adults....
View Full Document

This note was uploaded on 10/03/2010 for the course CHEM 527 taught by Professor Starnes,s during the Fall '08 term at Texas A&M University–Commerce.

Page1 / 45

Chapter 3 (part 2) - Chapter 3 (part 2) Protein...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online