Amino acids: Difference between revisions
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[[Single letter amino acid codes|Amino acids]] are the building blocks of [[Proteins|proteins]]. There are 20 naturally occurring amino acids. (1) Amino acids exist in [[Proteins|proteins]] as [[L-optical isomers|L-optical isomers]], however they can extist as [[D-isomers|D-isomers]] in isolated examples. E.g. some [[Bacteria|bacterial]] cell walls contain D-isomers. | [[Single letter amino acid codes|Amino acids]] are the building blocks of [[Proteins|proteins]]. There are 20 naturally occurring amino acids. (1) Amino acids exist in [[Proteins|proteins]] as [[L-optical isomers|L-optical isomers]], however they can extist as [[D-isomers|D-isomers]] in isolated examples. E.g. some [[Bacteria|bacterial]] cell walls contain D-isomers. | ||
Amino acids can also be characterized as [[Polar|polar]] or [[Non-polar|non-polar]], these dictate the amino acid function. There are 10 [[Non-polar amino acids|non-polar amino acids]], these are found in [[Protein|protein]] core. There are also 10 [[Polar amino acids|polar amino acids]], these have enzymatic roles, they can be used to bind [[DNA|DNA]], metals and other naturally occuring ligands. There are [[Essential amino acids|essential amino acids]] and [[Non-essential amino acids|non-essential amino acids]]. [[Essential amino acids|Essential amino acids]] are the ones that the body cannot synthesise on its own. These amino acids have to be supplied to the body via digested proteins. The digestion of cellular proteins is also an important source for amino acids. Non-essential amino acids can be synthesised from compounds already existing in the body.<br> | Amino acids can also be characterized as [[Polar|polar]] or [[Non-polar|non-polar]], these dictate the amino acid function. There are 10 [[Non-polar amino acids|non-polar amino acids]], these are found in [[Protein|protein]] core. There are also 10 [[Polar amino acids|polar amino acids]], these have enzymatic roles, they can be used to bind [[DNA|DNA]], metals and other naturally occuring ligands. There are [[Essential amino acids|essential amino acids]] and [[Non-essential amino acids|non-essential amino acids]]. [[Essential amino acids|Essential amino acids]] are the ones that the body cannot synthesise on its own. These amino acids have to be supplied to the body via digested proteins. The digestion of cellular proteins is also an important source for amino acids. Non-essential amino acids can be synthesised from compounds already existing in the body.<br> | ||
Amino acids have been abbreviated into a 3 letter code as well as a 1 letter code. For example, [[Glycine|Glycine]] has the 3 letter code 'Gly' and is assigned the letter 'G' (see [[Single letter amino acid codes|single letter amino acid codes]]).<br> | Amino acids have been abbreviated into a 3 letter code as well as a 1 letter code. For example, [[Glycine|Glycine]] has the 3 letter code 'Gly' and is assigned the letter 'G' (see [[Single letter amino acid codes|single letter amino acid codes]]).<br> | ||
=== '''List of Amino acids, their charges and side chain polarity:'''<br> === | === '''List of Amino acids, their charges and side chain polarity:'''<br> === | ||
[[Alanine|Alanine]] (A) '''Charge = ''''''Polarity = nonpolar'' | [[Alanine|Alanine]] (A) '''Charge = ''''''Polarity = nonpolar'' | ||
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[[Lysine|Lysine]] (K) '''Charge''' = positive. '''Polarity''' = polar | [[Lysine|Lysine]] (K) '''Charge''' = positive. '''Polarity''' = polar | ||
[[Leucine|Leucine]] (L) '''Charge''' = neutral. '''Polarity '''= nonpolar<br> | [[Leucine|Leucine]] (L) '''Charge''' = neutral. '''Polarity '''= nonpolar<br> | ||
[[Methionine|Methionine]] (M) '''Charge'''= neutral.'''''<i>P'</i>'''olarity '''= nonpolar<br> | [[Methionine|Methionine]] (M) '''Charge'''= neutral.'''''<i>P'</i>'''olarity '''= nonpolar<br> | ||
[[Asparagine|Asparagine]] (N) '''Charge '''= neutral. '''Polarity '''= polar | [[Asparagine|Asparagine]] (N) '''Charge '''= neutral. '''Polarity '''= polar | ||
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[[Arginine|Arginine]] (R) '''Charge''' = positive. '''Polarity '''= polar | [[Arginine|Arginine]] (R) '''Charge''' = positive. '''Polarity '''= polar | ||
[[Serine|Serine]] (S) '''Charge''' = neutral. '''Polarity '''= nonpolar<br> | [[Serine|Serine]] (S) '''Charge''' = neutral. '''Polarity '''= nonpolar<br> | ||
[[Threonine|Threonine]] (T) Charge = neutral. '''Polarity''' = polar | [[Threonine|Threonine]] (T) Charge = neutral. '''Polarity''' = polar | ||
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[[Valine|Valine]] (V) '''Charge''' = neutral. '''Polarity '''= nonpolar | [[Valine|Valine]] (V) '''Charge''' = neutral. '''Polarity '''= nonpolar | ||
[[Tryptophan|Tryptophan]] (W) '''Charge '''= neutral. '''Polarity '''= nonpolar<br> | [[Tryptophan|Tryptophan]] (W) '''Charge '''= neutral. '''Polarity '''= nonpolar<br> | ||
[[Tyrosine|Tyrosine]] (Y) '''Charge '''= neutral. '''Polarity '''= polar<br> | [[Tyrosine|Tyrosine]] (Y) '''Charge '''= neutral. '''Polarity '''= polar<br> | ||
=== '''Amino acid structure''' === | === '''Amino acid structure''' === | ||
All amino acids have a carboxyl terminus, and an amino terminus, but they differ in their residual groups. Amino acids are bonded together by a [[Covalent|covalent]] linkage called a [[Peptide bond|peptide bond]] <ref>Alberts, B et al. (2008). Molecular Biology of the Cell. 5th ed. US: Garland Science. 1268. (Page 59)</ref>. Amino acids contain both a [[Carboxyl group|carboxyl group]] (COOH) and an [[Amino group|amino group]] (NH<sub>2</sub>).<br> | All amino acids have a carboxyl terminus, and an amino terminus, but they differ in their residual groups. Amino acids are bonded together by a [[Covalent|covalent]] linkage called a [[Peptide bond|peptide bond]] <ref>Alberts, B <i>et al.</i> (2008). Molecular Biology of the Cell. 5th ed. US: Garland Science. 1268. (Page 59)</ref>. Amino acids contain both a [[Carboxyl group|carboxyl group]] (COOH) and an [[Amino group|amino group]] (NH<sub>2</sub>).<br> | ||
=== References: === | === References: === | ||
<references /><br> | <references /><br> | ||
Revision as of 12:28, 14 November 2011
Amino acids are the building blocks of proteins. There are 20 naturally occurring amino acids. (1) Amino acids exist in proteins as L-optical isomers, however they can extist as D-isomers in isolated examples. E.g. some bacterial cell walls contain D-isomers.
Amino acids can also be characterized as polar or non-polar, these dictate the amino acid function. There are 10 non-polar amino acids, these are found in protein core. There are also 10 polar amino acids, these have enzymatic roles, they can be used to bind DNA, metals and other naturally occuring ligands. There are essential amino acids and non-essential amino acids. Essential amino acids are the ones that the body cannot synthesise on its own. These amino acids have to be supplied to the body via digested proteins. The digestion of cellular proteins is also an important source for amino acids. Non-essential amino acids can be synthesised from compounds already existing in the body.
Amino acids have been abbreviated into a 3 letter code as well as a 1 letter code. For example, Glycine has the 3 letter code 'Gly' and is assigned the letter 'G' (see single letter amino acid codes).
List of Amino acids, their charges and side chain polarity:
Alanine (A) Charge = 'Polarity = nonpolar
Cysteine (C) Charge =neutral.Polarity = nonpolar
Aspartic Acid (D) Charge =negative.Polarity = polar
Glutamic Acid (E) Charge = negative. Polarity = polar
Phenylalanine (F) Charge = neutral. Polarity = nonpolar
Glycine (G) Charge = neutral. Polarity = nonpolar
Histidine (H) Charge = neutral. Polarity = polar
Isoleucine (I) Charge = neutral. Polarity = nonpolar
Lysine (K) Charge = positive. Polarity = polar
Leucine (L) Charge = neutral. Polarity = nonpolar
Methionine (M) Charge'= neutral.P'olarity = nonpolar
Asparagine (N) Charge = neutral. Polarity = polar
Proline (P) Charge = neutral. Polarity = nonpolar
Glutamine (Q) Charge = neutral. Polarity = polar
Arginine (R) Charge = positive. Polarity = polar
Serine (S) Charge = neutral. Polarity = nonpolar
Threonine (T) Charge = neutral. Polarity = polar
Valine (V) Charge = neutral. Polarity = nonpolar
Tryptophan (W) Charge = neutral. Polarity = nonpolar
Tyrosine (Y) Charge = neutral. Polarity = polar
Amino acid structure
All amino acids have a carboxyl terminus, and an amino terminus, but they differ in their residual groups. Amino acids are bonded together by a covalent linkage called a peptide bond [1]. Amino acids contain both a carboxyl group (COOH) and an amino group (NH2).
References:
- ↑ Alberts, B et al. (2008). Molecular Biology of the Cell. 5th ed. US: Garland Science. 1268. (Page 59)