PROTEIN SHAPEPROTEIN STRUCTUREAND

ENZYMES

Proteins Part II

Essential, Nonessential, and Conditional

Essential – must be consumed in the dietNonessential – can be synthesized in the bodyConditionally essential – cannot be synthesized due to

illness or lack of necessary precursors

Types of proteins

PROTEIN SHAPE/ Structure of the Protein

Functional protein consists of one or more

polypeptides precisely twisted, folded and coiled.

Denaturation is the process in

which a protein unravels and loses its normal shape.

Changes in pH and

temperature

Bonds between amino acids (from monomers to polymers)

chemical reaction: Dehydration Reaction

Structure of the Protein Any alteration

in the structure

or sequencing changes the shape

and function

of the protein

Denaturing

Alteration of the protein´s shape and thus functions through the use of HeatAcidsBasesSaltsMechanical

agitation

Denaturing a Protein

ENZYMES

Weaken chemical bonds.

Molecules absorb energy.

“start-up” energy is called Activation energy.

Heating up would cause unnecessary reactions to occur at once.

Catalysts (compounds that speed up reactions).

Lowers the energetic requirement.

Lock and key.

Specific substrate for the enzyme.

HOW DO ENZYMES WORK?

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

Quick Review Proteins are chains of combination of amino acids

Amino acids contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur

Unique amino acids consist of a central carbon with a carboxyl group, a hydrogen, a nitrogen-containing amine group, and a unique side chain

There are 20 side chains and 20 unique amino acids

9 essential amino acids

11 nonessential amino acids

At time these become conditionally essential

Amino acids link together with peptide bonds by condensation and break apart by hydrolysis

Quick Review

Attractions and interactions between the side chains cause the proteins to fold into precise three-dimensional shapes

Protein shape determines its functionProteins are denatured and their shapes

changed byHeat

Acids

Bases

Salts

Mechanical agitation

Quick Review

Protein structure has 4 levels:

a)Primary structure

b)Secondary structure

c)Tertiary structure

d)Quaternary structure

Denaturation is the Alteration of the protein´s shape and thus functions through the use of Heat

Acids

Bases

Salts

Mechanical agitation