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By :
Nindi mediartika (E1M009006)
Lutviya zun rain (E1M009018)
Mujadalah (E1M009038)
a Amino acid
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What is Amino acid?
Amino acids play central roles both as buildingblocks of proteins and as intermediates inmetabolism.
Structure :Atom C a. Called as a because adjacent with carboxyl
group ( acid).
Atom H which attached at atom C a.
Carboxyl group which attached at atom C a.
Amino group which attached at atom C a.
R group that is also attached at atom C a.
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Structure an amino acid
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Anatomy of an a-aminoacid
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R group different sidechainin each amino acid type
The different R group determines:
Structure
Measure
Charge of electric
Underwater condensationcharacter
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Standard amino acids
Amino acid compilingorganism protein is 20kinds of conceived ofstandard amino acid
Known amino acid to 21called as selenosistein (seldom be found) There isin some enzymes like
gluthatione peroxidase Selenenosistein has
genetic code: UGA
http://en.wikibooks.org/wiki/File:Molecular_structures_of_the_21_proteinogenic_amino_acids.svg -
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http://en.wikibooks.org/wiki/File:Molecular_structures_of_the_21_proteinogenic_amino_acids.svg -
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The Classification of amino acids
Amino acids can be classified by R Group
knowledge of the chemical properties of thestandard amino acid is central to an
understanding of bichemistry. The topic can besimplified by grouping the amino acids into fivemain classes based on the properties of their Rgroup, in particular, their polarity or tendency to
intract with water at biological pH (near pH 7.0).The polarity of the R groups varies widely, fromtotally nonpolar or hydrophobic (water insoluble)to highly polar or hyrophilic (water soluble)
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Non-polar, Aliphatic Rgroup
Has aliphatic R group
Hydrophobic
The side chain of alanine, valine, leucine, and
isoleucine tend to cluster together withinproteins, stabilizing protein structure by meansof hidrophobic interaction.
Glycine has the simplest structure.
Metheionine, one of the two sulfur-containingamino acid, has a non-polar thioeher group inits side chain.
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Non-polar, Aliphatic R group
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Aromatic R group
Relatively non polar (hidrophobic)
The hidroxyl group of tyrosine can formhydrogenbond
The important functional group in someenzymes
Tyrosine and triptophan are significantly more
polar than phenilalanine because of thetyrosine hidroxyl group and the nitrogen oftriptophan indole ring.
Aromatic amino acid can permeate [light/ray]UV 280 nm often applied to determine
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Aromatic R group
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Polar, uncharged R group
More soluble in water/more hydrophilicthey contain functional groups that formhydrogen bond with water.
Serine, threonine, cysteine, asparagine, andglutamine.
The polarity of Serine, and threonine is
contriuted by theirnhydroxil group, cysteine byits sulfhydril group, asparagine, and glutamineby their amide groups.
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Polar, uncharged R group
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Positively charged R group
Lysine, arginine, and histidine
Have basic side chain (R) Group.
Polar; hydrophilic located in proteinsurface.
Histidine is the only standard a.a having anionizable side chain with a pKa near neutraly
(has an amidazole group) Lysine amino group
Arginine guanidino group
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Positively charged R group
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Negatively charged R group
Aspartate and glutamate.
Has a second carboxyl group which ionized isfull (negative charge at pH 7.0).
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Non standard amino acids
Created by modification of standard residuesalready incorporated into a polypeptide.
Among the Non standard amino acids are 4-
hydroxyproline, a derived of proline and 5-hidroxylysine, derived from lysine.
The former is found in plant cell wall proteins,
and both are found in collagen, a fibrousprotein of connective tissues.
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Non standard amino acids
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Peptide Bond
Two a.a molecules can be covalently joinedthrought a subtituted amide linkage, termedpeptide bond, to yield a dipeptide.
3/4/5/6,. a.a are joined called oligopeptide When many a.a are joined the product called
polypepide
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Peptide Bond
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references
http://www.biology.arizona.edu/biochemistry/problem_sets / aa/aa.html
http://www.heruswn.teach-nology.com
Lehninger, A.L., Nelson, D.L., Cox, M.M. , 1993. Principlesof Biochemistry. New York :Worth Publisher.
Matta, M.K., dkk. 1996. Intoduction to General, Organic, and BiologicalChemistry. New York : D.C. Healt and Company.
Murray R.K., dkk. 2003. Biokimia Harper Edisi 25. Jakarta : PenerbitBuku Kedokteran EGC.
http://www.heruswn.teach-nology.com/http://www.heruswn.teach-nology.com/http://www.heruswn.teach-nology.com/http://www.heruswn.teach-nology.com/ -
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WASSALAM.......
THANK YOU FORATTENTION