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''' Polar amino acids'''<br>There are twenty amino acids, five of which are polar but uncharged. Two of which contain a [[Hydroxyl group|hydroxyl group]] (-OH) attached to [[Aliphatic side chain|aliphatic side chain]] that is ''[[Serine|serine]] ''and ''[[Threonine|threonine]]''. As for the [[Asparagine|''asparagine'']] and [[Glutamine|''glutamine'']] they contain a terminal carboxamide in place of carboxylic acid. The fifth polar amino acid is ''[[Cysteine|cysteine]]'' that is structurally similar to [[Serine|serine]] but contain a [[Sulfhydryl|sulfhydryl]], or [[Thiol|thiol]] (-SH), instead of the [[Hydroxyl|hydroxyl]] (-OH) group <ref>Berg J., Tymoczko J and Stryer L, (2007) Biochemisty, 6th edition, New York: WH freeman.</ref>. </b> | ''' Polar amino acids'''<br>There are twenty amino acids, five of which are polar but uncharged. Two of which contain a [[Hydroxyl group|hydroxyl group]] (-OH) attached to [[Aliphatic side chain|aliphatic side chain]] that is ''[[Serine|serine]] ''and ''[[Threonine|threonine]]''. As for the [[Asparagine|''asparagine'']] and [[Glutamine|''glutamine'']] they contain a terminal carboxamide in place of carboxylic acid. The fifth polar amino acid is ''[[Cysteine|cysteine]]'' that is structurally similar to [[Serine|serine]] but contain a [[Sulfhydryl|sulfhydryl]], or [[Thiol|thiol]] (-SH), instead of the [[Hydroxyl|hydroxyl]] (-OH) group <ref>Berg J., Tymoczko J and Stryer L, (2007) Biochemisty, 6th edition, New York: WH freeman.</ref>. </b> All amino acids in solutions of a neutral pH form dipolar ions called zwitterions, the amine group being positive and the carboxyl group negative. | ||
'''Polar amino acids''' | '''Polar amino acids''' | ||
Revision as of 06:38, 10 January 2011
Polar amino acids
There are twenty amino acids, five of which are polar but uncharged. Two of which contain a hydroxyl group (-OH) attached to aliphatic side chain that is serine and threonine. As for the asparagine and glutamine they contain a terminal carboxamide in place of carboxylic acid. The fifth polar amino acid is cysteine that is structurally similar to serine but contain a sulfhydryl, or thiol (-SH), instead of the hydroxyl (-OH) group [1]. </b> All amino acids in solutions of a neutral pH form dipolar ions called zwitterions, the amine group being positive and the carboxyl group negative.
Polar amino acids
| Serine | Ser | S |
| Cysteine | Cys | C |
| Threonine | Thr | T |
| Glutamine | Gln | Q |
| Asparagine | Asn | N |
References
- ↑ Berg J., Tymoczko J and Stryer L, (2007) Biochemisty, 6th edition, New York: WH freeman.