Chapter 5 Definitions/Concepts Flashcards Preview

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Flashcards in Chapter 5 Definitions/Concepts Deck (36)
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1

Ligand

A molecule bound reversibly by a protein, can be any kind of molecule

2

Binding Site

Where the ligand binds the protein. Complementary to the ligands size, shape, charge and hydrophobic/hydrophilic characteristics.

3

Binding Specificity

Ligand binding to a binding site is usually highly specific

4

Multiple Binding Sites

Proteins can have more than one binding site to bind more than one kind of ligand

5

Conformational Changes

Conformational changes can be subtle or dramatic and are essential for protein function

6

Induced Fit

A change in the proteins binding site that makes the binding of the ligand more desirable

7

Substrates

The molecules acted upon by an enzyme in a reaction

8

Heme

Prosthetic group for binding oxygen, found in hemoglobin and myoglobin

9

Cooperative Bonding

When one O2 is bound it triggers the other subunits from T state to R state, therefore increasing the affinity for more O2 to bind.

10

T State

Conformation that is more stable in the absence of oxygen

11

R State

Conformation that has a higher binding affinity for oxygen

12

Allosteric Protein

Binding of the ligand to one site affects the binding properties of another site on the same protein

13

Oxygen binding pressure

The partial pressure of oxygen in the lungs and tissues affect its ability to bind to hemoglobin

14

Hill Coefficient

Measures the degree of cooperatively. When it equals 1 binding is not cooperative. When it is greater then 1 binding is cooperative.

15

Inverse Hemoglobin Binding Relationship

The binding of H and CO2 is inversely proportional to the binding of O2. When the pH is low and CO2 concentration is high the tissues decrease the affinity of hemoglobin for O2, therefore releasing it into the tissue.

16

H binding on hemoglobin

Doesn't bind to heme group. Binds to any of the amino acids which causes the structure to favor the T state.

17

CO2 binding to hemoglobin

Doesn't bind to heme group. Binds to N-terminal end of any of the 4 polypeptide chains

18

CO binding to hemoglobin

Does bind to heme group with higher affinity then oxygen, therefore reducing oxygen concentration in the body

19

Sickle Cell Anemia

Hereditary disease with abnormal shaped and fewer erythrocytes. Caused by amino acid substitution in the beta chains, creating hemoglobin s.

20

Hemoglobin S

Has fewer negative charges, protein aggregates into long fibers

21

Antigen

Molecule or pathogen capable of eliciting an immune response

22

Epitope

The part of an antigen the antibody recognizes

23

Immunoglobin G

Major class of antibody comprised of 4 polypeptide chains, 2 heavy and 2 light. Connected by disulfide bonds and non-covalent interactions to form a y-shaped molecule

24

Fab

Part of the immunoglobin G, has amino acids that recognize and bind antigens

25

Antibody-antigen specificity

Conferred by chemical complementarity between antigen and specific binding site

26

Model of Induced Fit Binding

Conformational changes occur to facilitate the most favorable interactions. Shape can change greatly when antigen is introduced

27

Antibody-Antigen Binding

Kd is very small, they bind tightly

28

Polyclonal

Many different antibodies recognizing different epitopes of the same antigen

29

Monoclonal

A single antibody recognizing a single epitope of an antigen

30

Stationary Phase

Uses antibodies to bind and retain a protein (antigen) of interest