Proteins Flashcards
The breakdown of molecule into smaller units
catabolic
Monomers of proteins
amino acid
Cells in the liver
Hepatocytes
Sub-cellular level processes
mitochondria
ribosome
Metabolic fuels
Carbohydrates
Lipids
Proteins
Proteins -> Amino acids ->
Carbohydrates or Lipids (vice versa)
Proteins are __________ occurring
Naturally
Protein is a/n ________ polymer
Unbranched
The organelle where protein synthesis occurs
Ribosomes
Aids in the attachment of amino acids to make polypeptide chain
tRNA (Transfer RNA)
Has the instruction to synthesize unbranched proteins
Genes
Proteins are the _________organic molecules
Most abundant
Proteins constitute _________ of the cellular dry
weight
50%
The word protein comes from
Greek word “proteios”
Meaning of proteios
holding the first place/ primary
suggested the name proteins to the group of organic compounds that are utmost important to life
Berzelius (Swedish chemist) 1838
used the term proteins for the high molecular weight nitrogen-rich and most abundant substances present in animals and plants
Mulder (Dutch chemist) 1838
Elemental Composition Carbon:
50 – 55%
Elemental Composition Hydrogen:
6 – 7.3%
Elemental Composition Oxygen:
19 – 24%
Elemental Composition Sulfur:
0 – 4%
Protein may contain
P,
Fe,
Cu,
I,
Mg,
Mn,
Zn
Contains the iron in hemoglobin
Heme
Polypeptide chain in hemoglobin
globin
catalyzed by enzymes, which contain protein
Biochemical reactions
- made of the protein group collagens (most abundant in human body)
Structure of cells and the extracellular matrix
Time taken by biological reactions to occur without enzymes
2.3 billion years
Biological Importance of Proteins
- Biochemical reactions
- Structure of cells and the extracellular matrix
- Transport of materials in body fluids
- Antibodies
(most abundant protein in human body)
collagens
Collegen molecules shape
Triple helices
Collagen Synthesis
- Translation
- Hydroxylation
- Glycosylation
Taking insufficient amounts of vitamin C may cause
weak collagen fibers (Scurvy)
Defective lysyl hydroxylase gene
Ehlers-Danlos syndrome
Ehlers-Danlos syndrome
Weak vessel walls (prone to aneurysm)
Hyperflexible joints
Hyperextensible skin
Transport of materials in body fluids Examples:
transferrin
transmembrane proteins
transcription factors
receptor for hormones
transmembrane proteins
initiate the transcription of a gene
transcription factors
major component of the immune system
Antibodies
Ability to bind ___________ specifically & strongly to ___________
small molecules; themselves
ASA can strongly bind to
Albumin
Drug-bound protein
Not active
Free drug
Active
Ability to bind _________ & form _________ structures
other proteins; fiber-like
Examples of bind other proteins
Collagen
Albumin
Ability to bind & be integrated into _________
cell membranes
Classification by Protein Functions
- Catalytic Proteins:
- Regulatory Proteins:
- Transport Proteins
- Defense Proteins:
- Structural Proteins
- Storage proteins
- Transmembrane proteins
- Nutrient Proteins
- Contractile and Motile Proteins
Enzymes released to the _______ in tissue damage
blood
Enzymes are important _________ tool
diagnostic
Alanine aminotransferase (ALT) former name
serum glutamic pyruvic transaminase (SGPT)
Aspartate Aminotransferase (AST) former name
serum glutamate oxalate transaminase (SGOT)
increase in cirrhosis and fatty liver, heart failure
Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST)
More specific to liver disease
Alanine Aminotransferase (ALT)
More sensitive in tests for cirrhosis and fatty liver, heart
failure
Aspartate Aminotransferase (AST)
increases after myocardial infarction
Lactate dehydrogenase
sensitive to partial or mild biliary obstruction, liver
carcinoma or bone disease
Alkaline phosphatase (ALP)
other name for biliary obstruction
tissue damage
Chemical messengers that control the actions of specific cells or organs
Hormones
Affect growth and development, metabolism, sexual function, reproduction, and behavior
Hormones
Transmit signals to coordinate biochemical processes between different cells, tissues & organs
Hormones
Tested in the clinical laboratory in
blood, urine, or saliva
Hormones
stimulates sperm production and follicle maturation
follicle stimulating hormone (FSH)
produced by the placenta after implantation detected in pregnancy test
human growth hormone (HGH)
stimulates glycogen metabolism in liver
Glucagon
stimulates lactation
Prolactin
Hormones activate
G protein
G protein triggersthis from ATP
cAMP
cAMP transmits
CREB
Other name for plasma membrane
biologic membrane
Transport Proteins examples
ions,
small molecules, or
macromolecules
transports oxygen
Hemoglobin
Active site of hemoglobin
Heme
most abundant protein in human blood plasma
Albumin
Albumin function
transporting fatty acids, and other compounds,
acting as a buffer, and
maintaining osmotic pressure
transports iron through the
blood plasma
Transferrin
Defense Proteins:
Immunoglobulins/Antibodies
Blood-clotting proteins, thrombin and fibrinogen
Defense Proteins Produced by ________ in the bone marrow
B cells (lymphocytes)
Mediate the humoral immune response to identify and neutralize foreign objects
Defense Proteins
humoral means
blood
majority of the antibodies responsible for resistance against many viruses, bacteria, and bacterial toxins
IgG
first antibody secreted after an antigen is encountered;
responsible for the agglutination of incompatible blood types
IgM
COVID-19 Rapid Antibody Test (RAT): detects the presence
of
IgM and IgG
released in response to allergy
IgE:
found in the surface of B cells where it can bind to antigens in the extracellular fluid and signals the B cells to be activated
IgD
found primarily in glandular secretions and attach antigens before they gain access to internal organs
IgA
glandular secretions
colostrum,
mucus,
tears,
saliva and
semen
Blood-clotting proteins:
thrombin
Fibrinogen →
fibrin → formation of a fibrin clot
-Primary purpose of coagulation
hemostasis
(to stop bleeding from a damaged blood vessel)
structures of cells and tissues (muscle, tendons, and bone matrix)
Fibrous proteins
Provide strength and protection to cells and tissues
Fibrous proteins
insoluble fibrous proteins in hair, horns, and fingernails
Keratins
insoluble fibrous protein in bone, connective tissue, tendons, and cartilage,
Collagen:
Collagen is _______ of the total protein in a vertebrate
animal
One-third
forms inelastic fibrils of great strength
Collagen
component of ligaments
Elastin
allows tissues to resume shape after stretching or contracting
helps skin to return to its original position
Elastin
Serve as reserves of metal ions and amino acids
Released and used later without harm occurring to cells during the time of storage
Storage proteins
stores iron to be later used in the manufacture of hemoglobin
Ferritin
Ferritin diagnostic tool for
iron deficiency anaemia (IDA)
Elastin is found in what layer of the skin
Dermis
Responsible for moving substances such as nutrients and electrolytes across the membrane
Act as receptors that bind hormones and neurotransmitters
Transmembrane proteins
How many ferric ions can ferritin store
4500
Two general types of membrane proteins:
Integral membrane protein
Peripheral membrane protein
penetrates the cell membrane
partially or completely from one side to the other side of the lipid bilayer
Integral membrane protein
- non-penetrating membrane protein
- located on the surface
Peripheral membrane protein
Provide a reservoir of an essential nutrient
Provide sufficient nitrogen for growth
Nutrient Proteins
most abundant (3/4) protein of milk
major nitrogen source for mammalian infants
Casein
Other component of milk other than casein
Whey
found in egg white particularly important in the early stages of
life from embryo
Ovalbumin:
Ovalbumin: accounts over
50%
Casein has how many amino acid
209
Provide cells with unique capabilities for movement:
Contractile and Motile Proteins
movement
Cell division,
muscle contraction, and
cell motility
filamentous proteins forming the contractile systems of cells
Actin and Myosin
Globular protein
Major component of microtubules
Enables a cell to undergo mitosis or to regulate intracellular transport:
Tubulin
Tubulin Move
vesicles,
granules,
organelles (mitochondria, and chromosomes)
- Composed of only amino acid residues
- Globular or fibrous in shape
Simple Proteins
amino acid residue means
no ions or molecules attached
- Spherical or oval in shape
- Soluble in water or other solvents and digestible
Globular
Produces amino acid residue
Condesation
Globular Function
transporters,
enzymes, and
messengers
Globular Examples
albumin,
hemoglobin, and
the immunoglobulins
Soluble in water and dilute salt solutions and coagulated
by heat.
Albumins:
Albumins: examples
e.g. serum albumin, ovalbumin (egg), lactalbumin (milk).
Soluble in neutral and dilute salt solutions
Globulins:
Globulins: examples
e.g. serum globulins, vitelline (egg yolk).
Soluble in dilute acids and alkalies and mostly found in plants
Glutelins:
Glutelins: examples
e.g. glutelin (wheat), oryzenin (rice).
Soluble in 70% alcohol
Prolamines:
Prolamines: examples
e.g. gliadin (wheat), zein (corn)
Small proteins for structural support for chromosome
-Strongly basic proteins, soluble in water
Histones:
Histones: Contains _______ → forms a _______ with DNA
arginine and lysine; complex
complex of DNA and proteins
Chromatin:
organization of eukaryotic DNA into chromatin is essential for controlling
transcription and packaging
-Generally considered along with histones
-Not basic proteins
Globins
-Strongly basic
-Resemble histones but smaller in size
-Found in association with nucleic acids e.g. sperm proteins
Protamines:
-Carbohydrate-binding proteins
-Involved in the interaction between cells and proteins
-Maintain tissue and organ structures
Lectins
the word lectin comes from
(Latin-‘Legree’ = to pick or select).
_________ in cell surfaces act as a lectins
receptor
Glycoconjugates
Form long protein filaments or subunits
Asymmetrical and usually inert
Fibrous
Fibrous Generally
water insoluble (hydrophobic R groups)
Fibrous are mainly
structural (connective tissues, tendons, bone, and muscle)
- connective tissue proteins lacking tryptophan
Collagens:
Collagens: boiled →
gelatin (soluble and digestible)
- found in elastic tissues such as tendons and arteries
Elastins:
present in exoskeletal structures
Keratins:
*Human hair keratin:
14% cysteine
predominant group of fibrous proteins.
Albuminoids or scleroproteins:
Contain a non- protein moiety known as prosthetic group
Conjugated Proteins
Nitrogen containing molecukes
porphyrins,
Prosthetic group: nucleic acid
Nucleoproteins
Nucleoproteins: examples
nucleohistones, nucleoprotamines
-Prosthetic group: carbohydrate
-Less than 4% of protein
Glycoproteins:
*mucoprotein: examples
mucin (saliva), ovomucoid (egg white).
carbohydrate content is more than 4%.
mucoprotein
-Prosthetic group: lipids
Lipoproteins:
Lipoproteins: examples
serum lipoproteins
-Prosthetic group: Phosphoric acid
Phosphoproteins:
Phosphoproteins: examples
casein (milk), vitelline (egg yolk).
-Prosthetic group: coloured in nature
Chromoproteins:
Chromoproteins: examples
hemoglobins, cytochromes
-Contain metal ions such as Fe, Co, Zn, Cu, Mg:
Metalloproteins:
Metalloproteins: example
ceruloplasmin (Cu), carbonic anhydrase (Zn)
One peptide chain
Monomeric protein
Monomeric protein example
ribonuclease,
lysozyme,
hexokinase
Large proteins – many amino acid residues
Multimeric protein
▪Peptide chains are called
protein subunits
Insulin has ____ protein subunits
2
How many amino acids in lysozyme
129
