PRE FI LEC 1: PROTEINS Flashcards
PROTEINS IN THE HUMAN BODY
- fight invaders
ANTIBODIES
PROTEINS IN THE HUMAN BODY
- system of 20 PROTEIN molecules that are activated during INFECTIONS
COMPLEMENT SYSTEM
PROTEINS IN THE HUMAN BODY
- Signaling proteins
- communicate with other cells
CYTOKINES
PROTEINS IN THE HUMAN BODY
- proteins in the muscle
- interaction with each other for muscle movement
ACTIN & MYOSIN
PROTEINS IN THE HUMAN BODY
- proteins in the muscle
- release oxygen to muscle
MYOGLOBIN
PROTEINS IN THE HUMAN BODY
- proteins in the muscle
- stores and release oxygen
FERRITIN
PROTEINS IN THE HUMAN BODY
- proteins in the blood
- transport oxygen
HEMOGLOBIN
PROTEINS IN THE HUMAN BODY
- proteins in the blood
- clots blood
FIBRINOGEN
PROTEINS IN THE HUMAN BODY
- proteins in blood
- maintain proper amount of liquid in blood
ALBUMIN
PROTEINS IN THE HUMAN BODY
- helps break down food
DIGESTIVE ENZYMES
PROTEINS IN THE HUMAN BODY
- form channels for substances to move through membrane
- act as enzymes
- act as receptors
CELL MEMBRANE
PROTEINS IN THE HUMAN BODY
Cell membrane 3 types of protein?
PERIPHERAL PROTEIN
INTEGRAL PROTEIN
LIPID - BOUND PROTEIN
PROTEINS IN THE HUMAN BODY
- structural protein
- network of protein filament and tubules that maintain cell shape
CYTOSKELETON
PROTEINS IN THE HUMAN BODY
- structural protein
- found in skin, hair, and nails
KERATIN
PROTEINS IN THE HUMAN BODY
- structural protein
- provides strength
COLLAGEN
PROTEINS IN THE HUMAN BODY
- structural protein
- provides flexibility
ELASTIN
CHARACTERISTICS OF PROTEINS
- A protein is a naturally-occurring, unbranched polymer in
which the monomer units are?
AMINO ACIDS
CHARACTERISTICS OF PROTEINS
- Proteins are most abundant molecules in the cells after water
(__% of a cell’s overall mass)
15 %
Elemental composition of a protien
CARBON, HYDROGEN, OXYGEN, NITROGEN, SULFUR (CHONS)
Other elements found in protein are?
IRON (Fe), PHOSPHORUS (P) & some other metals in some specialized protein
STRUCTURE of an AMINO ACID is composed of:
- 2 functional groups?
AMINE (NH2) & CARBOXYLY GROUP (COOH)
STRUCTURE of an AMINO ACID is composed of:
○ 2 functional groups: Amine (NH2) and Carboxyl (COOH) Group
○ Side chain or R group
○ Alpha carbon atom
CLASSIFICATION
- aka hydrophobic amino acids
NONPOLAR AMINO ACIDS
CLASSIFICATION
- non-charged AAs
POLAR NEUTRAL AMINO ACIDS
CLASSIFICATION
- NEGATIVELY charged at physiological pH
–COOH group in the residue is ionized into
–COO- at cellular pH
POLAR ACIDIC AMINO ACIDS
CLASSIFICATION
- POSITIVELY charged at physiological pH
–NH2 group in the residue is ionized into
–NH3+ at cellular pH
POLAR BASIC AMINO ACIDS
NONPOLAR AMINO ACIDS
- GLYCINE
- VALINE
- ALANINE
- LEUCINE
- ISOLEUCINE
- METHIONINE
- PROLINE
- PHENYLALANINE
- TRYPTOPHAN
POLAR NEUTRAL AMINO ACIDS
- SERINE
- THREONINE
- TYROSINE
- CYSTEINE
- ASPARAGINE
- GLUTAMINE
POLAR ACIDIC ACIDS
- ASPARTIC ACID
- GLUTAMIC ACID
POLAR BASIC AMINO ACIDS
- HISTIDINE
- LYSINE
- ARGININE
widely used for naming
3-LETTER ABBREVIATION
commonly used for comparing amino acid sequence of proteins
1-LETTER ABBREVIATION
HOW MANY ESSENTIAL AMINO ACIDS ARE THERE?
9
HOW MANY NON - ESSENTIAL AMINO ACIDS ARE THERE?
11
not naturally occurring, source: dietary intake
ESSENTIAL AMINO ACIDS
naturally occurring, produced by the body
NON - ESSENTIAL AMINO ACIDS
ESSENTIAL AMINO ACIDS
- PHENYLALANINE
- HISTIDINE
- ISOLEUCINE
- LEUCINE
- METHIONINE
- THREONINE
- TRYTOPHAN
- VALINE
- LYSINE
CONDITIONALLY NON - ESSENTIAL AMINO ACIDS
- ARGININE
- ASPARAGINE
- GLUTAMINE
- GLYCINE
- PROLINE
- SERINE
- TYROSINE
NON - ESSENTIAL AMINO ACIDS
- ALANINE
- ASPARTATE
- CYSTEINE
- GLUTAMATE
- an ion with + (positive) and – (negative) charges on the same molecule with a net zero charge
ZWITTERIONS
- Under physiological conditions, amino acids exists as Zwitterions
- Carboxyl groups _________ a proton to get negative charge
- Amino groups ___________ a proton to become positive
GIVE-UP; ACCEPT
– pH at which the concentration of Zwitterion is maximum - net charge is zero
ISOELECTRIC POINT (pI)
- Chemically unique amino acid
- the only standard amino acid with a sulfhydryl group ( — SH group)
CYSTEINE
Cysteine in the presence of MILD OXIDIZING AGENTS dimerizes to form a ____________ molecule.
CYSTINE
are short chains of amino acids linked by
peptide bonds.
PEPTIDES
- are longer, continuous chains of peptide
- have a molecular mass of 10,000 Da or more are
called proteins
POLYPEPTIDE
The covalent bonds between amino acids in a peptide are called _____________
PEPTIDE BONDS OR AMIDE
bond between two amino acids
DIPEPTIDE
bond between ~ 10 - 20 amino acids
OLIGOPEPTIDE
bond between large number of amino acids
POLYPEPTIDE
Every peptide has an ________________ & ______________
N-TERMINAL END; C-TERMINAL END
Biochemically important SMALL PEPTIDES
- HORMONES
- NEUROTRANSMITTERS
- ANTIOXIDANTS
- released into the bloodstream as a hormone in
response to sexual activity and during labor (HORMONE)
OXYTOCIN
- antidiuretic hormone that helps fluid retention in
the body to balance water volume and osmolality (HORMONE)
VASOPRESSIN
are pentapeptide neurotransmitters produced by
the brain and bind receptors within the brain; help reduce pain (NEUROTRANSMITTERS)
ENKEPHALINS
- a tripeptide, present in high levels in most cells, a regulator of oxidation–reduction reactions
- is an antioxidant and protects cellular
contents from oxidizing agents such as peroxides
and superoxides
GLUTATHIONE (Glu-Cys-GLy)
A protein in which only amino acid residues are present:
More than one protein subunit may be present but all subunits contain only amino acids
SIMPLE PROTEINS
A protein that has one or more non-amino acid entities (prosthetic groups)
- One or more polypeptide chains may be present
~ Non-amino acid components - may be organic or inorganic - prosthetic groups
Examples: lipoproteins, glycoproteins and metalloproteins
CONJUGATED (COMPLEX PROTEINS
STRUCTURE OF PROTEIN
- Refers to the order in which amino acids are linked together in a protein; every protein has its own unique amino acid sequence
PRIMARY STRUCTURE
STRUCTURE OF PROTEIN
- 2 most common types : alpha-helix and the beta-pleated sheet
SECONDARY STRUCTURE
A single protein chain adopts a shape that resembles a coiled spring
ALPHA - HELIX (a-HELIX)
Completely extended amino acid chains
BETA- PLEATED SHEETS
STRUCTURE OF PROTEIN
- The overall three-dimensional shape of a protein
Results from the interactions between amino acid side chains (R groups) that are widely separated from each other
TERTIARY STRUCTURE
4 TYPES OF INTERACTION OBSERVED IN A TERTIARY STRUCTURE
- DISULFIDE BONDING
- ELECTROSTATIC INTERACTIONS
- H-BONDING
- HYDROPHOBIC INTERACTIONS
- refers to the organization among the
various polypeptide chains in a multimeric protein:
~ Highest level of protein organization
~ Present only in proteins that have 2 or more polypeptide chains (subunits)
~ are often referred to as oligomeric
proteins
QUATERNARY STRUCTURE
