Biochemistry Name: __________________NDHS Per: _______ Date: ________

PROTEINS:Molecular Tools of Cells

Function:1.2.3.4.5.6.7. ***** *******• Enzymes

– Are a type of protein that acts as a catalyst, speeding up chemical reactions

Structure of a Protein: __________________ - chain of __________________

Four parts of amino acid1. __________________2. __________________3. __________________4. __________________

- DISTINGUISHES ONE AA FROM ANOTHER - a.k.a. - gives specific

- some __________________ - can be acidic or basic- some __________________

- ________________________________________________ ________________________________________________

- carboxyl and amino change with pH of environment- very acidic amino and carboxyl have H+- as increase in pH # of H+ decreases so H+ dissociate until

reaches no H+ on amino or carboxyl- point in between where amino group is changed and

carboxyl is not is called

Zwitterion:

Protein Isoelectric Point:

Zwitterion results when the _____________________________ ___________________________________________________

The exchange of hydrogen ions by the amino acids allow proteins to __________________________________ in the blood and cytoplasm of cells

Normal biological pH range is ______ – outside of that range most proteins will begin to __________________________

In all three cases, the amino acid has a __________ which makes it ______________________.

If the pH changes enough, the amino acid may gain/lose H+ enough that they become _______________________ and ______________________________________

This is known as the protein’s ________________________

Blood Chemistry:

Blood is filled with soluble proteins that act as ______________ ____________________

Hemoglobin in RBC have an isoelectric point of a ___________

Normal blood ___________

Increased CO2 concentration will lower the ________________ (H2O + CO2 H2CO3 – carbonic acid)

○ Chemosensors in the _________________________ _________________monitor the pH of the blood

○ If it begins to drop (too much CO2), a signal is sent to the diaphragm and intercostal muscles of the lungs to contract more and increase breathing rate

BUILDING A PROTEIN Process called __________________ AA bond by __________________ between

__________________ FORM A __________________ As the proteins are built they take on different

________________ based on the AA sequence and the _________________________

Resulting structure will determine function

STRUCTURE OF A PROTEIN1. ______________ : sequence of - determined by genetic information of DNA- change in one AA can alter function2. _________ : _________________________ - from interactions of Hydrogen bonds between amino and carboxyl groups of AA

alpha helix - spiral pleated sheets - two regions of the chain lie next to one

another forming folds

3. : interactions that hold the different areas of a protein together

hydrogen bondshydrophobic region attracted to one anotherVan der WaalsDisulfide bridges - bonds between two sulfurs in R

groups – Between 2 cysteine AASTRONG _____________

Ionic Bonds between R groups4. :

putting other proteins together in a ______________- EX: ____________________________________

Shaping of the protein aided by ___________________________________________

-direct the conformation of the protein

Sickle-cell disease- Results from a single amino acid substitution in the

protein hemoglobin

What Determines Protein Conformation?- Depends on the physical and chemical conditions of the

protein’s environment

Environmental Effects on Protein Structure_________________ - changing the protein so it is no __________

__________________ - cause protein to unravel by breaking interlinking bonds

DENATURATION _________________________ :

Heat causes the molecules to vibrate more and _______________________________ at the secondary level and then _________________ together (cooked egg)

Collagen: made of 3 helical strands ○ Heat causes the strands to break and make random

coiled formations trap water making gelatin

______________________ : Acids and bases alter the ionic chargesDetergents solubilize the hydrophobic regions disrupting

their structureSpoiled Milk:Natural bacteria in milk grow and produce acids. As the

population of bacteria gets high enough, the acids cause the proteins in the milk to reach their isoelectric point and precipitate. ○ Also the basis of making cheese and yogurt.

Medical Application of Denaturation1) __________ : denature the proteins in bacteria and viruses2) __________ (hand sanitizer):

70% ETOH will enter the bacteria and denature the proteins

95% ETOH denatures the surface proteins3) _______________ : Raw egg or milk are ingested to treat

Pb+2, Cu+2, and Hg+2 poisoning. The metals bind to the proteins forming clumps that can be pumped or vomited out, which must be done before the proteins are digested which would rerelease the ions.

ENZYMES: Regulate all of metabolismTypes of Enzymes

1) _____________________ : carry out RedOX rxns2) _____________ : move functional groups between molecules3) _____________ : carry out hydrolysis4) _____________ : form or break double bonds5) _____________ : convert molecules into isomers6) __________________ : create bonds by dehydration synthesis

Additions to Enzymes- most enzymes, once made by protein synthesis, require additional changes to make the active1) _________________: enzymes that require a cofactor or coenzyme to activate them

___________ = ______________________ = ___________

2) _________________: inactive enzymes that must have their structure altered to make them functional

Ex: Pepsinogen must be altered in the stomach to make it into Pepsin for protein digestion. H+ cleave the amino end (N-Terminus) of the protein

Enzymes and Sulfa Drugs Bacteria and humans need ____________ as an important co-

enzyme The molecule ________________ is toxic to both humans

and bacteria Sulfa drugs such as Sulfathiozine and Sulfapyridine are less

toxic and readily absorbed by bacteria. Bacteria readily convert the sulfa drugs into a faulty form of

folic acid that then _______________ with regular folic acid as a co-enzyme. This is known as _____________________.

This inhibition causes the bacterial enzymes to fail and the bacteria die.

Enzymes and Poisons Mercury and Lead bind to the active site of an enzyme and

permanently bind to them causing them to stop working. ______________________ puts a chelating agent such as

EDTA (Ethylene Diamine Tetra Acetic Acid) to bind up the metals before they can affect the enzymes

Side Note: Some antibiotics can act as chelators. Ciprofloxiacin and other fluoroquinolones will bind to

Calcium and become inactive. Can’t eat or drink calcium rich foods several hours

before or after taking the antibiotic or they will be rendered ineffective.

The Enzyme War:The Penicillin Resistance- Penicillin was accidentally discovered by Alexander Fleming in 1929 when working with bread mold.

Penicillin works by inhibiting the enzyme _______________ which is responsible for crosslinking the proteins in the _________________ wall of the bacteria.

Since the wall of the bacteria is weaker, the cytoplasm of the cell leaks out and the bacteria dies.

Due to the over use of penicillin, some bacteria became resistant through the use of an enzyme called ____________ _______________________, which breaks the beta-lactam ring in penicillin making it ineffective.

To counter the resistance, artificial penicillins with extra R-groups on the beta lactam ring to protect it from the beta lactamase so the penicillin does not fit in the enzymes active site.

A more effective approach has been the use of ___________________ which also has a beta lactam ring.

When bacteria cleave the beta lactam ring in clavulanic acid, it binds __________________ to the beta lactamase enzyme competitively inhibiting it.