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What is an example of a quaternary level of structure?
Human hemoglobin has four subunits, tretramer.
Protein kinase is also a tetramer.
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Six examples of permanent chemical groups that associate with proteins?
- Lipoproteins
- Glycoproteins: IgG
- Phosphoproteins
- Hemoproteins: Hemoglobin
- Flavoproteins: Flavin nucleotides
- Metalloproteins: Iron, Ca, Copper
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Important initial facts how Amino Acids get into bloodstream?
- -First must go through enterocytes (cells that line the small intestine) at the brush border, which line the small intestine lumen.
- - Need to be coupled with Sodium, NA to enter into the cell, with the help of a "carrier", "transporter".
- -The carrier is called a symport because it transports the AA simultanously with the NA.
- - Sodium potassium pump is necessary to pump the "excess" sodium back OUT of the cell.
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How are dipeptides and tripeptides transported into the cytosol of the enterocyte?
Next step once inside?
Dipeptides and tripeptides must be co-transported with a "proton" (hydrogen)
Once in the cytosol of the cell, they are catabolized into amino acids.
The excess H protons are transported out with a Sodium, Hydrogen antiport.
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Activity at the Basolateral membrane of the enterocyte?
Some of the amino acids that were broken down from the di and tripeptides need to be co-transported out with sodium through a facilitated carrier.
There is a Sodium/Potassium pump on the enterocyte's basolateral membrane to bring potassium in and sodium out.
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What are the characteristics of Globular Proteins?
- Globular - water soluble
- - spherical
- - Complex interactions between secondary and tertiary structural elements
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Give four examples of globular proteins
- 1) Enzymes (kinase), biological catalyst
- 2) Hormones (insulin), regulate biological processes
- 3)Transport (albumin), carry molecules in plasma
- 4) Storage (ferratin) store and protect
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What are the characteristics of fibrous proteins?
Fibrous proteins are animal structural materials and water insoluble.
Unique structures obtained by combining special amino acids into regular, secondary structural elements.
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Give three examples of fibrous proteins in humans.
- 1) Collagens
- 2) Keratins
- 3) Elastins
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Characteristics and facts about collagens?
Collagen is the MOST ABUNDANT protein in the body.
Forms connective tissue: bones, tendons, ligaments, cartilage.
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Examples of keratin in the body?
Keratin makes up protective tissue, such as skin, hair, nails.
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Examples of where elastin proteins are in the human body.
Elastin can be found in:
- - Aorta
- - Large arteries
- - Ligamentum flavum
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Describe collagen construction
- Triple helix, about 1000 amino acids long
- Most abundant protein
- Glycine makes 1/3 of collagen
- Very strong hydrogen bonding between polypeptide chains because of small size of glycine, increases hydrogen bond strength
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What are examples of Type I Collagen?
Hallmark characteristic of this type?
Type 1: Has tensile strength
- - Skin
- - Bone
- - Ligaments
- - Tendons
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Examples of Type II Collagen and characteristic
Type II: Resists compression
- - Cartilage
- - Intervertebral disk
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Example of Type III Collagen?
Blood vessel walls
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Example of Type IV Collagen?
Found in the basement membrane of cells.
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In the biosynthesis of collagen, how is the collagen formed, and where?
Collagen is formed by fibroblasts and secreted into the extracellular matrix
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What is the (repeated) sequence of the polypeptide of collagen?
- Glycine-Proline- a) hydroxyproline
- b) hydroxylysine
( a and b are Derived Amino Acids ONLY found in collagen)
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What are the two enzymes needed to put hydroxyl groups on prolyl residues?
- Prolyl hydroxylase
- Lyso hydroxylase
(hydroxylase is enzyme that helps to form the bond between the OH group and proline)
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What is the cofactor necessary to put the hydroxyl group on prolyl residues
Need ascorbate acid, Vitamin C, to hydroxylate prolyl
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What is Scurvy and it's symptoms.
- Scurvy: deficiency of ascorbic acid, vitamin C
- Tensile strength of collagen fibers can't connect, "cross link" as well due to lack of hydrogen bonding
- -Sore spongy gums
- - Loose teeth
- - Fragile blood vessels
- - Bruises
- - Anemia
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