Amino AcidsAmino Acids

Characteristics and StructuresCharacteristics and Structures

Amino AcidsAmino Acids

There are 20 amino acids derived from proteinsThere are 20 amino acids derived from proteins . .

While there are several methods of categorizing themWhile there are several methods of categorizing them , ,

one of the most common is to group them according to the nature of their side chainsone of the most common is to group them according to the nature of their side chains..

11--Nonpolar Side ChainsNonpolar Side Chains

22--Polar, Uncharged Side ChainsPolar, Uncharged Side Chains

33--Charged Side ChainsCharged Side Chains

Amino AcidsAmino Acids

11 - -Nonpolar Side ChainsNonpolar Side Chains

There are eight amino acids with nonpolar side chainsThere are eight amino acids with nonpolar side chains..

Glycine, alanine, and prolineGlycine, alanine, and proline

have small, nonpolar side chains and are all weakly hydrophobichave small, nonpolar side chains and are all weakly hydrophobic . .

Phenylalanine, valine, leucine, isoleucine, and methioninePhenylalanine, valine, leucine, isoleucine, and methionine

have larger side chains and are more strongly hydrophobichave larger side chains and are more strongly hydrophobic..

Amino AcidsAmino Acids

22 - -Polar, Uncharged Side ChainsPolar, Uncharged Side Chains

There are also eight amino acids with polar, uncharged side chainsThere are also eight amino acids with polar, uncharged side chains . .

Serine and threonineSerine and threonine have hydroxyl groups have hydroxyl groups . .

Asparagine and glutamineAsparagine and glutamine have amide groups have amide groups..

Histidine and tryptophanHistidine and tryptophan have heterocyclic aromatic amine side chains have heterocyclic aromatic amine side chains..

CysteineCysteine has a sulfhydryl group has a sulfhydryl group . .

Tyrosine Tyrosine has a phenolic side chain has a phenolic side chain . .

Amino AcidsAmino Acids

33 - -Charged Side ChainsCharged Side Chains

There are four amino acids with charged side chainsThere are four amino acids with charged side chains . .

Aspartic acid and glutamic acidAspartic acid and glutamic acid

have carboxyl groups on their side chainshave carboxyl groups on their side chains . .

Arginine and lysineArginine and lysine

have side chains with amino groupshave side chains with amino groups . .

NameNameAbbreviationAbbreviationLinear StructureLinear Structure

Alanineala Aala ACH3-CH(NH2)-COOHCH3-CH(NH2)-COOH

Argininearg Rarg RHN=C(NH2)-NH-(CH2)3-CH(NH2)-HN=C(NH2)-NH-(CH2)3-CH(NH2)-COOHCOOH

Asparagineasn Nasn NH2N-CO-CH2-CH(NH2)-COOHH2N-CO-CH2-CH(NH2)-COOH

Aspartic Acidasp Dasp DHOOC-CH2-CH(NH2)-COOHHOOC-CH2-CH(NH2)-COOH

Cysteinecys Ccys CHS-CH2-CH(NH2)-COOHHS-CH2-CH(NH2)-COOH

Glutamic Acidglu Eglu EHOOC-(CH2)2-CH(NH2)-COOHHOOC-(CH2)2-CH(NH2)-COOH

Glutaminegln Qgln QH2N-CO-(CH2)2-CH(NH2)-COOHH2N-CO-(CH2)2-CH(NH2)-COOH

Glycinegly Ggly GNH2-CH2-COOHNH2-CH2-COOH

Histidinehis Hhis HNNH-CH=N-CH=H-CH=N-CH=CC-CH2-CH(NH2)-COOH-CH2-CH(NH2)-COOH

Isoleucineile Iile ICH3-CH2-CH(CH3)-CH(NH2)-COOHCH3-CH2-CH(CH3)-CH(NH2)-COOH

NameNameAbbreviationAbbreviationLinear StructureLinear Structure

Leucineleu Lleu L(CH3)2-CH-CH2-CH(NH2)-COOH(CH3)2-CH-CH2-CH(NH2)-COOH

Lysinelys Klys KH2N-(CH2)4-CH(NH2)-COOHH2N-(CH2)4-CH(NH2)-COOH

Methioninemet Mmet MCH3-S-(CH2)2-CH(NH2)-COOHCH3-S-(CH2)2-CH(NH2)-COOH

Phenylalaninephe Fphe FPh-CH2-CH(NH2)-COOHPh-CH2-CH(NH2)-COOH

Prolinepro Ppro PNNH-(CH2)3-H-(CH2)3-CCH-COOHH-COOH

Serineser Sser SHO-CH2-CH(NH2)-COOHHO-CH2-CH(NH2)-COOH

Threoninethr Tthr TCH3-CH(OH)-CH(NH2)-COOHCH3-CH(OH)-CH(NH2)-COOH

Tryptophantrp Wtrp WPhPh-NH-CH=-NH-CH=CC-CH2-CH(NH2)-COOH-CH2-CH(NH2)-COOH

TyrosineTyrosinetyr Ytyr YHO-Ph-CH2-CH(NH2)-COOHHO-Ph-CH2-CH(NH2)-COOH

ValineValineval Vval V(CH3)2-CH-CH(NH2)-COOH(CH3)2-CH-CH(NH2)-COOH

Amino AcidsAmino Acids

Importance of Amino AcidsImportance of Amino Acids

Amino acids are the building blocks of protein and you get protein from your dietAmino acids are the building blocks of protein and you get protein from your diet..

If you eat a variety of healthy protein-containing foodsIf you eat a variety of healthy protein-containing foods , ,

you will get all of the eight essential amino acids that your body can't make for itselfyou will get all of the eight essential amino acids that your body can't make for itself..

Amino acids combine into small chains via chemical reactions calledAmino acids combine into small chains via chemical reactions called

' ' condensation reactionscondensation reactions‘‘ in which the carboxyl group and the amino group bond to one in which the carboxyl group and the amino group bond to one

another. These small chains that contain a few amino acids linked together are calledanother. These small chains that contain a few amino acids linked together are called

polypeptide chains (the individual amino acids are called petides)polypeptide chains (the individual amino acids are called petides)..

Polypetide chains, in turn, combine into the more complex structures know as proteinsPolypetide chains, in turn, combine into the more complex structures know as proteins

Amino AcidsAmino Acids

Amino AcidsAmino Acids

Essential and Nonessential Amino AcidsEssential and Nonessential Amino Acids

Nonessential amino acids are those that are synthesized by mammalsNonessential amino acids are those that are synthesized by mammals , ,

while the essential amino acids must be obtained from dietary sourceswhile the essential amino acids must be obtained from dietary sources

The twenty amino acids can be divided into two groups of 10 amino acidsThe twenty amino acids can be divided into two groups of 10 amino acids . .

Ten are essential and 10 are nonessential. However, this is really notTen are essential and 10 are nonessential. However, this is really not

accurate , as there is overlap between the two groupsaccurate , as there is overlap between the two groups..

Amino AcidsAmino Acids

      The Ten "Nonessential" Amino Acids

Alanine    

Asparagine

Aspartate

Cysteine    (requires sulfhydryl group from methionine)

Glutamate

Glutamine

Glycine

Proline

Serine

Tyrosine     (synthesized from phenylalanine)

       The Ten "Essential" Amino Acids

Arginine  (see below)

Histidine

Isoleucine

Leucine

Lysine

Methionine

Phenylalanine

Threonine

Tryptophan

Valine

Only twoExamples Will be Enough

Amino AcidsAmino Acids

Strecker amino acid synthesisStrecker amino acid synthesis

Amino AcidsAmino Acids

Amino AcidsAmino Acids