PRE FI LEC 2: PROTEINS AND PROTEIN METABOLISM Flashcards
PROTEIN CLASSIFICATION BASED ON SHAPE
- are protein molecules with peptide chains that are folded into SPHERICAL or GLOBULAR shapes
- water solubles (because the hydrophobic amino acids residues of this protein are hidden in the protein core and what is shown outside is the hydrophilic amino are residue
- function as enzyme and intra cellular signalling molecules
Ex: MYOGLOBIN & HEMOGLOBIN
GLOBULAR
- is an oxygen storage molecules in muscle
- monomers are single peptide chain with heme unit so that is why it is capable of holding and transporting of oxygen
- binds one oxygen molecule
- 1 heme unit = 1 molecule of oxygen binding
- higher affinity of oxygen compared to hemoglobin
- serve as reserve oxygen source for working muscles
MYOGLOBIN
- is oxygen carrier molecule in the blood- transport oxygen from the lungs to various tissue of our body
- it has a unique structure because it is tentramer (4 polypeptide chains) each sub unit is a heme group
- 1 hemoglobin = 4 heme unit = 4 oxygen
- can transport 4 O2 at a time
- iron in heme interacts with oxygen
HEMOGLOBIN
PROTEIN CLASSIFICATION BASED ON SHAPE
- protein molecules with elongated shape
- insoluble in water (because the hydrophobic amino acid residue are exposed)
- single type of secondary structure of proteins
- simple and regular linear structures
- they tend to aggregate together to form macromolecules structure (aggregation contributes to rigid structure)
Ex: a-KERATIN & COLLAGEN
FIBROUS
FIBROUS
- provides protective coating for organs
- constituent of our nails and hair
- mainly made of hydrophobic amino acids residues that are hydrophobic that is why it is insoluble
- it’s hardness depends upon the SS bonds (disulfide bonds/bridges)
a - KERATIN
FIBROUS
- is the most abundant proteins in the body (30% of body protein)
- major structural material in our tendons, ligaments, blood vessels and our skin
- the more intake of collagen, the more glowing your skin appears to be
- organic component of bones and teeth
- rich in proline, it’s constitute up to 20%
Proline: important the structure
COLLAGEN
PROTEIN CLASSIFICATION BASED ON SHAPE
- this membrane proteins associated with cell membranes
- insoluble of water ( predominantly composed of hydrophobic amino acid on the surface)
- water insolubility of the memebrane helps in the transport of molecules in the membrane
Ex: Membrane proteins
MEMBRANOUS
WHAT ARE THE PROTEINS CLASSIFICATION BASED ON FUNCTION
- CATALYTIC
- DEFENSE
- TRANSPORT
- MESSENGER
- CONTRACTILE
- STRUCTURAL
- TRANSMEMBRANE
- STORAGE
- REGULATORY
- NUTRIENT
PROTEINS CLASSIFICATION BASED ON FUNCTION
- responsible for catalyzing reactions
- hastens chemical reactions
ex: ENZYMES
CATALYTIC
PROTEINS CLASSIFICATION BASED ON FUNCTION
- involves our immune systems
ex: IMMUNOGLOBULINS (or ANTIBODIES) & COMPLEMENT SYSTEM
- together they help fight foreign bodies or antigens
DEFENSE
PROTEINS CLASSIFICATION BASED ON FUNCTION
- binds small molecules such as oxygen
- transport them to other location of the body and release them based on the body demands
ex: MYOGLOBIN, HEMOGLOBIN, TRANSFERRIN
- helps transport of oxygen molecules in certain organs that needs oxygen
TRANSPORT
PROTEINS CLASSIFICATION BASED ON FUNCTION
- transmit signals to coordinate biochemical processes between different cells, tissues, and organs
ex: INSULIN & GLUCAGON - helps in regulation of carbohydrates metabolism
GROWTH HORMONES - regulation of body’s growth
MESSENGER
PROTEINS CLASSIFICATION BASED ON FUNCTION
- necessary for all forms of movement
- muscle contains the filament like contractile proteins such as ACTIN and MYOSIN
- in human reproduction it depends on the movement of the sperm
CONTRACTILE
PROTEINS CLASSIFICATION BASED ON FUNCTION
- confers stiffness and rigidity
ex: COLLAGEN & KERATIN (gives mechanical strength as well as protective covering to our hair nails, etc.)
STRUCTURAL
PROTEINS CLASSIFICATION BASED ON FUNCTION
- spans cell membrane and helps the movement of small molecules and ions
ex: CHANNEL PROTEINS and MEMBRANE- BOUND PROTEINS
- this proteins ahs channels which help molecules to enter and exit the cell, but the transport and passage of substances is very SELECTIVE
- ion-selective (they allow passage of certain type of molecule or ions based on their reactions that they facilitated
TRANSMEMBRANE
PROTEINS CLASSIFICATION BASED ON FUNCTION
- bind and store molecules
ex: FERRITIN - iron storage protein, saves iron for use of the biosynthesis of new hemoglobin molecules
MYOGLOBIN - oxygen storage protein
HEMOGLOBIN - oxygen binder and storage molecule
STORAGE
PROTEINS CLASSIFICATION BASED ON FUNCTION
- acts as site for receptor molecules
-these molecules often that binds to enzymes
- controls enzymatic activity (turn off/on)
- helps in the catalytic function of enzyme
REGULATORY
PROTEINS CLASSIFICATION BASED ON FUNCTION
- important in early stages of life (from embryo to infant)
ex: CASEIN - protein found in milk
OVALBUMIN - found in egg white
- milk contains certain immunoglobulin that when transferred to infants will contribute to his immunity
NUTRIENT
- reverse peptide bond formation
- results in the generation of a carboxylic acid and an amine group
- breaking covalent bonds
- addition of water molecules (responsible for cleaving the bond between the molecules)
- does not affect the biological activity of the protein
summary: breaking down of proteins into smaller peptides or amino acid by addition of water molecule
HYDROLYSIS
- occurs when exposed to extreme temperature, pH changes or certain molecules
- involves physical/chemical change that alters the structure of the protein, often result to the loss of biological activity
- unfolding of proteins
- partial or complete disorganization of protein’s tertiary structure
- coagulation: precipitation (denaturation of proteins)
- cooking: kills microorganisms by denaturation of proteins
- cooking food denatures the protein but does not change protein nutritional value
DENATURATION
contributes to the hydrolysis of proteins
ENZYMATIC REACTIONS & CHEMICAL REACTIONS
HYDROLYSIS OR DENATURATION
DEFINITION: is the process of proteins LOSING THEIR SHAPE
PROTEIN DENATURATION
HYDROLYSIS OR DENATURATION
DEFINITION: is the process of BREAKING PROTEINS into their building blocks of AMINO ACIDS
PROTEIN HYDROLYSIS
HYDROLYSIS OR DENATURATION
WHAT HAPPENS: proteins lose its 3 dimensional structure and shape
PROTEIN DENATURATION
HYDROLYSIS OR DENATURATION
WHAT HAPPENS: proteins convert into amino acids
PROTEIN HYDROLYSIS
HYDROLYSIS OR DENATURATION
FACTORS AFFECTING: high temp., pH changes, denaturing agents, alkaline and acid solutions, etc.
PROTEIN DENATURATION
HYDROLYSIS OR DENATURATION
FACTORS AFFECTING: enzymes and chemicals
PROTEIN HYDROLYSIS
HYDROLYSIS OR DENATURATION
RESULT: loss of biological activity
PROTEIN DENATURATION
HYDROLYSIS OR DENATURATION
RESULT: production of free amino acids peptides
PROTEIN HYDROLYSIS