Proteins Flashcards
molecules w/ elongated shape & one dimension much longer
Fibrous Proteins
structure of fibrous proteins
Linear and form aggregate to form macromolecular structure
peptide chains folded into spherical or globule shapes
Globular Proteins
structure of globular proteins
Hydrophilic side chains on outside; hydrophobic in interior
found associated with a membrane system of a cell; opposite of globular protein
Membrane Proteins
fibrous vs. globular: water
fibrous - water soluble
globular - dissolve in water
Fibrous vs. globular: secondary structure
Fibrous - single type
Globular - several types
Fibrous vs. globular: function
Fibrous - support and external protection
Globular - involved in metabolism, transport, regulation, catalysis
5 fibrous proteins
Keratin, collagen, elastin, myosin, fibrin
Found in wool, feathers, hooves, silk, and nails
Keratin
Found in tendons, bones, and other connective tissues
Collagen
Found in blood vessels
Elastin
Found in muscle tissue
Myosin
Found in blood clots
Fibrin
5 common globular proteins
Insulin, myoglobin, hemoglobin, transferrin, immunoglobulins
Regulatory hormone for controlling glucose metabolism
Insulin
Involved in oxygen storage in muscles
Myoglobin
Involved in oxygen transport in blood
Hemoglobin
Involved in iron transport in blood
Transferrin
Involved in immune system responses
Immunoglobulins
Why are we able to remove lipids or cholesterols in the body?
Because they are bound with proteins which makes it easier to transport
Keratin structure
Coiling @ higher levels produce strength, intercoil disulfide bridge
Collagen
most abundant of all proteins in humans (30% of total body protein)
Characteristics of collagen
Rich proline content = triple helix conformation; form fibrils with cross linking on helices; stiffening of skin associated with aging
Predominant structure of collagen
Triple helix
Forms like a rope
Presence of glycine and proline
Structure of hemoglobin
- Tetramer (four peptide chains each contain heme group = binds to O2)
- Iron atom @ center interact w/ O2 ; 1 hemoglobin: 4 O2 molecules
Structure of myoglobin
- Single peptide chain & a heme unit hence carry one O2
- Higher affinity for O2 than hemoglobin; working muscles
Role of biochemical catalysts = enzymes
Catalytic proteins
immunoglobulins or antibodies function in immune
system
Defense proteins
Bind to small biomolecules and transport e.g. hemoglobin
Transport proteins
transmit signals to coordinate biochemical processes between different cells, tissues, and organ ex. Hormones
Messenger proteins
Necessary for movement. Filament like proteins in muscles, flagella of sperm
Contractile proteins
Stiffness and rigidity ex. Collagen & keratin
Structural proteins
@ cell membrane and control movement
Transmembrane proteins
Bind & store molecules for future use ex ferritin
Storage proteins
Important in early stages of life e.g casein in milk
Nutrient proteins
Site of binding for messenger proteins & enact function
Regulatory proteins
Necessary for movement. Filament like proteins in muscles, flagella of sperm
Contractile proteins
Maintain fluid balance between blood & tissue; e.g. albumin and globulin in capillary beds
Fluid-balance proteins
conjugated proteins that contain carbohydrates or carbohydrate derivatives in addition to amino acids
Glycoproteins
Collagen in glycoproteins
- attached sugar units by glycosidic linkages; related to cross linking
- Direct assembly of helices into complex aggregations = collagen fibrils
glycoprotein as a protective response to the invasion of microorganisms or foreign molecules; antigen = foreign substance vs. antibody
Immunoglobulin
- Conjugated proteins that are composed of both lipids and amino acids
- classified according to their density
Lipoproteins
involved in the transport system for lipids in the bloodstream
Plasma lipoprotein
Four major classes of plasma lipoprotein
Chylomicrons
Very-low-density lipoproteins
Low-density lipoproteins
High-density lipoproteins
transport dietary triacylglycerols from the intestine to the liver and to adipose tissue
Chylomicrons
Transport triacylglycerols synthesized in the liver to adipose tissue
Very-low-density lipoproteins (VLDL)
transport cholesterol synthesized in the liver to cells throughout the body
Low-density lipoproteins (LDL)
collect excess cholesterol from body tissues and transport it back to the liver for degradation to bile acids
High-density lipoproteins
Blood proteins that contain iron
Ferritin
Thick yellow secretion; high antibodies; more carbo
Colostrum
Protection in the cell membrane
Phospholipids
Free cholesterol content
Cystotoxic = contains toxic contents
Protective form of storage of the cell; helps transport plasma lipoprotein to other tissues and organs
Cholesterol esters
Excellent long term energy storage in the molecules made up of glycerol
Triglycerides
How to remove free cholesterol?
Bind with amino acids to easily transport to the liver which will be cleared and become a good cholesterol
