Module 13: Proteins

Proteins

are high molecular weight organic compounds made up of amino acids joined together by peptide linkages in a sequential order.

Proteios

proteins came from what Greek word?

Johannes Mulder

Who came up with the name protein from a Greek word “proteios"

STRUCTURAL PROTEINS

are important components of living structures that provide mechanical support to living bodies and provide them outer covering for protection.

Collagen

makes up the fibrous connective tissues in bones and cartilages

Elastin

makes up the elastic connective tissues in the skin, ligaments and blood vessels

Keratin

serves like a laminating material in the hair, nails, feathers, hooves and skin of animals

Sclerotin

makes up the exoskeletons of insects and other arthropods

STORAGE PROTEINS

also known as nutrient proteins

STORAGE PROTEINS

they serve as potential sources of biochemical energy and proteins, especially amino acids, for the maintenance of good health and for proper growth and living, especially infants or embryos

Ovalbumin

found in eggs

Casein

found in milk

Gliadin

found in wheat

Zein

found in corn

Ferritin – iron

iron containing protein found in lean meat

ENZYMES

organic or biological catalysts that enhance or stimulate particular chemical reactions involved in important metabolic processes

Cytochrome oxidase

responsible for the transport of electrons

Ribonucleases

used for the hydrolysis of RNA

Sucrase

– used for the hydrolysis of sucrose

Alcohol dehydrogenase

used for the fermentation of ethanol

Trypsin

hydrolyzes the polypeptide chain from the carboxyl end of arginine and lysine

Chymotrypsin

hydrolyzes the polypeptide chain from the carboxyl end of phenylalanine and tyrosine

HORMONES

chemical transmitter substances secreted by endocrine glands that has specific regulatory effects as to stimulate or retard life processes

Insulin

regulates the entry of glucose molecules to red blood cells

Growth hormone

promotes growth of muscles and bones

ACTH (adenocorticotropic hormone)

regulates the synthesis of corticosteroids

adenocorticotropic hormone

ACTH means?

ADH (antidiuretic hormone) / Vasopressin

promotes reabsorption of water from the kidneys, thus retards diuresis or urination

Vasopressin

other name for ADH

antidiuretic hormone

ADH means?

TRANSPORT PROTEINS

also known as carrier proteins,

Transport proteins

they deliver other important substances needed by a living body from a certain source to its proper site for storage or utilization in metabolic processes

Transcobalamin

transports vitamin B12 or cobalamin in the bloodstream

Transferrin

transports iron in the bloodstream

Ceruloplasmin

transports copper in the bloodstream

Lipoproteins

carrier molecules of lipids, primarily triglycerides and cholesterol

Hemoglobin

carries oxygen in the blood of vertebrates

Hemocyanin

carries oxygen in the blood of invertebrates

Myoglobin

transports oxygen in the muscle tissues

CONTRACTILE PROTEINS

proteins necessary for all forms of movement, voluntary or involuntary

Myosin

found in the thick and stationary filaments in the myofibril of skeletal muscles necessary for contraction

Actin

found in the thin and moving filaments in the myofibril of skeletal muscles necessary for contraction

Dynein

found in the locomotory appendages of microorganisms like the cilia and flagella

PROTECTIVE PROTEINS

they help the body to recover from injury like in the healing of wounds and to increase resistance or induce immunity from infectious diseases

Fibrinogen

precursor for fibrin threads necessary for blood clotting

Prothrombin

proenzyme of thrombin that converts fibrinogen into fibrin

Complement

set of proteins which aids in the formation of antigen – antibody (immune) complexes

Immunoglobulins

also known as antibodies

Immunoglobulins

produced by plasma cells used to protect the body from various types of infections

TOXINS

poisonous substances that can yield harmful effects to the body when taken such as intoxication or paralysis of living cells

Ricin

toxic protein found in castor bean

Botulism toxin

bacterial toxin produced by Clostridium botulinum that causes food poisoning

Diphtheria toxin

bacterial toxin produced by Corynebacterium diphtheriae that causes diphtheria

Snake venom

neurotoxin that contains enzymes that hydrolyzes phosphoglycerides

Clostridium botulinum

Botulism toxin is produced by?

Corynebacterium diphtheriae

Diphteria toxin is produced by?

SIMPLE PROTEINS

– true proteins found abundantly in both animals and plants that will yield amino acids only when hydrolyzed

Albumins

– soluble in water and neutral dilute salt solutions

Globulins

insoluble in water but soluble in neutral dilute salt solutions

Glutelins

soluble in dilute acids and alkalis but insoluble in neutral solvents

Prolamines

insoluble in ordinary solvents but soluble in 70% alcohol at about a neutral point

Histones

soluble in water, dilute acids and alkalis but not in dilute Ammonia

Protamines

soluble in water and dilute acids and alkalis and are not coagulated by heat

Scleroproteins

insoluble in water and neutral solvents

CONJUGATED PROTEINS

made up of simple protein molecules combined with non-protein groups (prosthetic group)

Nucleoproteins

combinations of histones and protamines with nucleic acid

Glycoproteins

proteins with a carbohydrate component utilized for lubricating purposes

Phosphoproteins

phosphate group joined to the protein molecule

Chromoproteins

protein compounds with hematin or other similar pigments

Lipoproteins

fatty substances combined with protein molecules

DERIVED PROTEINS

class of proteins formed from the hydrolysis of simple and conjugated proteins

Primary Protein derivatives

also known as denatured proteins

Primary Protein derivatives

have undergone slight intramolecular rearrangement through the hydrolytic action of certain physical and chemical agents

Proteans

insoluble substances resulting from the preliminary action of water, dilute acids or enzymes

Metaproteans (Infraproteans)

products of further hydrolysis that are soluble in weak acids and alkalis but insoluble in neutral salt solutions

Infraproteans

metaproteans is also called?

Coagulated proteins

insoluble products resulting from the action of heat, alcohol, ultraviolet radiation or even simple mechanical shaking

Secondary Protein derivatives

products of more extensive hydrolysis that are mixtures of original protein varying in composition and size

Primary proteoses

soluble in water and precipitated by concentrated HNO3 and half saturation with (NH4)2SO4 or ZnSO4; not coagulated by heat

Secondary proteoses

precipitated by complete saturation with (NH4)2SO4

Peptones

soluble in water and precipitated by saturation with certain alkaloidal reagents like phosphotungstic acid and tannic acid

Peptides

combinations of 2 or more amino acids, the carboxyl group of one being united with the amino group of the other

COMPLETE PROTEINS

are those that supply all the essential amino acids needed by the human body.

COMPLETE PROTEINS

They are capable of both maintaining life and providing normal growth when used as a sole protein food. Most are derived from animal sources.

PARTIALLY INCOMPLETE PROTEINS

are those that are capable of maintaining life but not supporting normal growth

INCOMPLETE PROTEINS

those that are deficient in one or more essential amino acids. They are incapable of maintaining life or supporting growth when fed as the sole protein source. Many proteins, especially those from vegetable sources, are incomplete.

COMPLETE PROTEINS

proteins made up of polypeptide chains arranged in a parallel fashion along a single axis, thus belong to the class of proteins that contain highly developed secondary structures.

COMPLETE PROTEINS

They are insoluble in water and in dilute salt solutions and are used mainly for structural purposes

GLOBULAR PROTEINS

proteins made up of polypeptide chains which are tightly folded into a compact spherical or globular shape, thus belong to a class of proteins that have a three dimensional tertiary structure.

GLOBULAR PROTEINS

They are soluble in water and most biologically active proteins for non-structural purposes belong to this classification

MIXED PROTEINS

PRIMARY STRUCTURE

refers to the linear sequential arrangement of amino acids in the polypeptide chain including the location of the disulfide bonds. It results from the covalent bonding between amino acids in the chain.

Peptide bonds

are amide bonds formed between the alpha-carboxylate group of one amino acid and the alpha amino group of another.

SECONDARY STRUCTURE

refers to the folding of the primary structure of proteins that results from the hydrogen bonding between the amine hydrogens and carbonyl oxygens of the peptide bonds.

ALPHA – HELIX

is the coiled, helical conformation of the secondary structure of protein oriented like a normal screw.

BETA – PLEATED SHEET

s the accordion like conformation of the secondary structure of protein.

Parallel -pleated sheet

the N termini are head to head

Anti-parallel -pleated sheet

the N terminus of one chain is aligned with the C terminus of the second chain (head to tail)

TERTIARY STRUCTURE

TERTIARY STRUCTURE

This overall three-dimensional structure results from the folding of the secondary structure that occurs spontaneously by a variety of interactions between amino acid side chains.