TEST 3 - PROTEAINS & ENZYMES Flashcards
Proteome
Set of expressed proteins in a particular cell or organism under a given set of environmental conditions.
Elements in Proteins
C, H, O, N, S
Monomers
Building Blocks = Amino Acids
Polymers
Polypeptide chains: 50 to 3k Amino Acids
Structural function of Proteins
- Components of all cell membranes
- Components of cytoplasm
- Components of movement
- Components of hair, nails, hormones, etc
Metabolic function of Proteins
- Hormones: regulatory chemical
- Energy transfer for cellular respiration
- Oxygen carrier in circulation
- Antibodies
- Enzymes***
Structure of an Amino Acid
- Central Carbon
- Hydrogen
- Amino Group (NH2)
- Carboxyl group (COOH)
- R group: functional group
Methionine
Amino Acid with SULFUR
Condensation Reaction
Amino Acid + Amino Acid = Two AA by peptide bond + Water
Peptide Bond
Forms from Condensation Reaction between AAs
Bond Between C-N
Varieties of of Possible Peptide Chains
- Primary Structure: straight
- Secondary structure: curly
- Tertiary structure: messy
- Quarterly structure: really messy
Hemoglobin Molecular Formula
C3032 H4816 O872 N780 S8 Fe4
Hemoglobin Structure
- Protein composed of 4 polypeptides (2 alpha and 2 beta globin chains), which is found in red blood cells.
- Quarteary Protein
- Globular Protein
- Conjugated Protein: Polypeptide & non-protein part
- Heme Group: Iron & Porphryinring
Function of Hemoglobin
Transport oxygen around the body
Immunoglobin
Anti-bodies. By white blood cells. Binding to antigens on bacteria.
Rhodopsin
Eye retina, light sensitive, pigment of red cells.
Collagen
Forms dermis of skin, fibrous proteins, 3 polypeptides, part of teeth bones
Keratine
Fibrous, 2 polypeptides, insoluble in water, hair, nails, claws.
Digestive Enzyme
Pepsin, Lipase, Amylase
Pepsin
Produced in the Stomach
Breaks down Polypeptides into AA
Lipase
Produced by the Pancreas
Released into the small intestine
Breaks down fats into fatty acids and glycerol
Amylase
Released by salivary glands in the mouth by the pancreas
Breaks down starch into maltose and glucose
Denaturing of Proteins
- Loss of the 3-dimensional structure and function and function of a protein (break down)
- May be permanent
- Results from an alteration of bonds that maintain 2ndary and 3rtiary structures
Causes for Denaturing of Proteins
- Strong acids and bases
- Heavy metals
- Heat and radiation (UV)
- Detergents and solvents
Dietary requirements for Amino Acids
- Essential Amino Acids cannot be synthesized and must be obtained
- Non-essential amino acids can be made from other amino acids.
Conditionally Essential AA
- Arginine
- Cysteine
- Glutamine
- Tyrosine
- Glycine
- Proline
- Serine
Essential AA
- Histidine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Isoleucine
- Leucine
- Valine
Non-Essential AA
- Alanine
- Asparagine
- Aspartic Acid
- Glutamic Acid
Metabolism
The “web of all the enzyme-catalyzed reactions in. cell or organism
- Anabolism: Synthesis
- Catabolism: Breakdown
Examples of Metabolism
- Photosynthesis
- DNA Replication
- Cell Respiration
- Decomposition
- Building muscle
- Protein Synthesis
- Digestion
- Fermentation
The role of enzymes in Metabolism
- Either Synthesize or Break down
- Make a biological reaction happen faster, making many processes more efficient.
> Enzymes are specific to their substrate (the reactant), so a large # of enzymes are required in an organism
Enzymes
- Act as a catalyst for metabolic reactions
- Are globular proteins with specific 3D formations
- Have a high specificity for substrate
- Proteins that are composed of building blocks that form long chains.
- Most enzymes end in “ASE”
Substrate
The molecule in which the enzyme acts
Helicase
Acts as a catalyst in DNA replication
Catalyst
Affects a chemical reaction without itself being changed (Re-Used)
Enzymes Functions
Regulate the rate at which reactions occur
Active Site
- Enzymes have an “active site” on the surface where the substrates readily interact.
- May have polar AA
Enzyme Substrate Specifity
Substrate is specific to the enzyme
Induced Fit Model
The shape of the enzyme accommodates to Substrate
- Active site is not a rigid pocket for the substrate to fit in.
- Substrate induces the enzyme to change shape
- Weaken the bonds of the substrate
- Lowers activation energy
Molecular motion and Substrate-active site collisions
- While some enzymes are emblazed and inmoblilized within a membrane, most enzymes and their substrate are found in solution (cytoplasm)
- Molecular movement is needed for a substrate and Active site to come together.
How do ENZYMES work?
- For a reaction to start it needs energy: ACTIVATION ENERGY.
- Enzymes lower this ACTIVATION ENERGY
- The amount of energy needed for a chemical reaction to proceed: ACTIVATION ENERGY
Enzymes and Reaction
Reactions are not impossible without enzymes
Enzymes just make the rate of reaction increase
Enzymes in reaction
- Substrates must absorb energy from their surroundings for their bonds to break
- Products release energy when their new bonds are formed.
Endergonic Reaction
- Absorbs energy into the reactions
- Amount of energy in the system increase
- Anabolic
Catalyzed Reactions
Hydrolytic reactions:
- Starch + Amylose = many maltose units
- Maltose + Maltase = Glucose + Galactose
- Lactose + Lactase = Glucose + Galactose
- Sucrose + Sucrase = Glucose = Fructose
Exergonic Reaction
- Gives off energy
- Represented by a negative charge in energy
- Loss of free energy
- Catabolic
Characteristics of Enzyme Activity
- Enzymes work best at certain temps and enable cell reactions to proceed at normal temps
- Small amount of enzyme can affect large amounts of substrate
- Enzyme and substrate concentration can control the rate of reaction
- Enzymes work best at certain pH
Effects of temperature on Enzymes Controlled Reactions
- Temp increases = Enzyme action increases: UNTIL optimum temp for the enzyme is reached
- Often doubling with every 10C rise
- “Collisions” between the substrate and the active site are more frequent at higher temps
- Exponential until optimum temp
> Rise: Inactive
> Top: Optimal temp
> Down: Denature
Effects of PH on Enzyme Controlled Reaction
- At other pHs enzymes are denatured because the H+ and OH- ions disrupt hydrogen bonds that hold the 3D structure
- Enzymes have an optimal pH in which they work best
- MOUNTAIN
> Rise: Denature
> Top: Optimal pH range
> Down: Denature
Effect of Substrate Concentration on Enzyme controlled Reacion
- As a substrate concentration increases, the rate of reaction of enzyme-catalyzed reactions will increase… and then become constant.
- The increased concentration is a “limiting factor”
- When substrates engage all the active sites, reaction rate will not increase
- HILL
> Top: Plateau (Saturation of substrate)
Pectinase
- Polysaccharide found in fruit skins (cell wall)
- Found in natural fungus (aspergillus niger) on fruit.
- Uses enzymes to soften food
- USES: Hydrolyzes pectin into monomers
Pectinase is added during the crossing of fruit - ADV: Makes juice clearer and increases volume.
Easy to separate from pulp.
Lactase
- Industrial lactase is produced from fungus: Kluyve Romyces Lactis
- Enzyme is “Immobilized”
- Added to milk. Concentration of milk drops. Glucose rises.
- ADV:
> Reduced intolerance
> Sweeter
> Less crystallization - Used in Ice cream
> Bacteria ferments glucose faster - Used in yougurt - Can be expensive
Biological Detergents
- Proteases-protein (Most dirt)
- Source: Bacteria-Bacillus Icheniformis.
- Contain enzymes to digest stains at lower temperatures than 45C and high PHs
- Wash in cold water! Lower energy use, less shrinking.
