Protein 1 of 3 - Students Copy

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 1/14

Schedule Activity

Feb 21 *Lecture (Protein Structure & Function Part 1 of 3)

*Short Exercise

Feb 26 *Pass assignment

*Quiz 1

*Lecture (Protein Structure & Function Part 2 of 3)

Feb 28 *Pass assignment

*Quiz 2

*Lecture (Protein Structure & Function Part 3 of 3)

Mar5 *Pass assignment*Quiz 3

*Lecture (Enzyme Part 1 of 2)

Mar 7 *Pass assignment

*Quiz 4

*Lecture (Enzyme Part 2 of 2)

Mar 11 *Pass assignment 

*Quiz 5

*Lecture (Nucleotide, DNA, RNA)

Mar15 *Checking and Recording

*Review of topics for Final Exam

Mar 21 Final Exam

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 2/14

PROTEINE STRUCTURE

&

FUNCTION Part 1 of 3

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 3/14

Protein

Proteins are large biological molecules consisting of one

or more chains of amino acids. Derived from a greek word that means “of first importance”. 

Provides an organism not only with C & H, but with N & S.

Most abundant macromolecule of the cell.

Carry most of the work of the cell.

Protects the body from infection, mechanical support and

strength, & catalysis of metabolic reactions - all are functions

of proteins that are essential to life.

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 4/14

Cellular Functions of Proteins

1. Enzymes are biological catalysts. Majority of the enzymes that

have been studied are proteins.

2. Defense protein include antibodies which are specific protein

molecules produced by specialized cells of the immune

system in response to foreign antigens.3. Transport proteins carry materials from one place to another.

4. Regulatory proteins control many aspects of cell function,

including metabolism and reproduction.

5. Structural proteins provide mechanical support to large animals

and provide them with outer covering.

6. Movement proteins are necessary for all forms of movement.

7. Nutrient proteins serve as sources of amino acids for embryos

or infants.

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 5/14

Structure of Amino Acids

Proteins of the body are made up of some combination of 20

different subunits called α-amino acids.

Orientation of almost all of the α-amino acids isolated proteins

in nature are members of the L-family.

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 6/14

Classes of Amino Acids

Class 1: Hydrophobic amino acids (9 amino acids)

glycine, alanine, valine, leucine, isoleucine, phenylalanine, proline,

tryphtophan, methionine

Class 2: Polar, neutral amino acids (6 amino acids)

serine, threonine, tyrosine, cysteine, asparagine, glutamineClass 3: Negatively charged amino acids (2 amino acids)

aspartate, glutamate

Class 4: Positively charged amino acids (3 amino acids)

lysine, arginine, histidine

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 7/14

Classes of Amino Acids

Class 1: Hydrophobic amino acids

Glycine (Gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleuc

Phenylalanine (Phe) Proline (Pro) Tryptohan (Trp) Methionine (Met

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 8/14

Classes of Amino Acids

Class 2: Polar, neutral amino acids

Serine (Ser) Threonine (Thr) Tyrosine (Tyr) Cysteine (Cys) Asparagine (Asn) Glutami

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 9/14

Class 3: Negatively charged amino acids

Aspartate (Asp) Glutamate

(Glu)

Classes of Amino Acids

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 10/14

Classes of Amino Acids

Class 4: Positively charged amino acids

Lysine (Lys) Arginine (Arg)

Histidine (His)

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 11/14

Peptide Bond

Consider the dehydration reaction of glycine and alanine:

Peptide bond is an amide bond formed between the  – COO- 

group of amino acid and the α-N+H3 group of another amino

acid.

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 12/14

Peptide Bond

N-terminal

amino acid

(Glycine)

C-terminal

amino acid

(Alanine)

Peptides are named as derivatives of the C-terminal amino acid,

which

receives its entire name. For all other amino acids, the ending – ineis

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 13/14

Steps in writing the structure of a peptide chain:

1) Write the backbone for a tripeptide.

2) Add oxygens to the carboxyl carbons and hydrogens to the

amino nitrogens

3) Add hydrogens to the α-carbons:4) Add the side chains.

Short Exercise: (Short yellow pad)

Write the structure of each of the following peptide:

1) lysyl-alanine

2) alanyl-glycyl-valine

3) phenylalanyl-tyrosyl-leucine

Peptide Bond

7/28/2019 Protein 1 of 3 - Students Copy

http://slidepdf.com/reader/full/protein-1-of-3-students-copy 14/14

Assignment

Research about α-helix and β-pleated sheet.

Include figures and diagrams.