52:蛋白质的基本单元--氨基酸
§2：蛋白质的基本单元－－氨基酸
Amino acids 20 different ones, sharing a common backbone but varying side chain carboxyl COO d ent amino end HgN—C—H c carbon Classed according to the L- form R side chain R R Lform D-form
Amino Acids 20 different ones, sharing a common backbone but varying side chain. Classed according to their chemical properties L-form
UPPSALA nonpolar amino acids R group consists of carbon chains H H3N-C-C H3N+c—c HaNC—c HaN° CH3 CH O CH2 H3C--CH CH3 CH3 CH2 CH3 CH3 CH3 GLYCINE( Gly) ALANINE(Ala) VALINE(Val) LEUCINE( Leu) IsoLEUCINE(Ile) leucine and isoleucine are structural isomers
nonpolar amino acids -R group consists of carbon chains leucine and isoleucine are structural isomers
UPPSALA nonpolar amino acids R group consists of carbon chains HaN—c—c H3N H C-C H2NC--c CH CH CH2o 2c、cHz CH 2 NH s CH3 METHIONINE(Met) PHENYLALANINE(Phe) TRYPTOPHAN(Trp PROLINE(Pro) Addison Wesley Longman. he phenylalanine and tryptophan have aromatic rings which are flat Methionine has a sulpha due to the double bond network Proline has its r group atom in its sidechain Tryptophan is often classified as bound to the amino sulphur has the same being polar because of the Nh nitrogen to form a ring valence as oxygen group. In practice, however it has network nore of hydrophobic properties
nonpolar amino acids - R group consists of carbon chains Phenylalanine and tryptophan have aromatic rings which are flat due to the double bond network Tryptophan is often classified as being polar because of the NH group. In practice, however it has more of hydrophobic properties Methionine has a sulphur atom in its sidechain sulphur has the same valence as oxygen Proline has its R group bound to the amino nitrogen to form a ring network
UPPSALA polar amino acids R group consists of carbon, oxygen and nitrogen atoms together they make the sidechain more hydrophilic H HNc-c、hN-c-c、HN-c-c、HaN"c HsN一c-c.HaNG-c o 构2 CH CH2 OH CH3 c CH2 NH2 o c SERINE THREONINE CYSTEINE TYROSINE ASPARAGINE GLUTAMINE (Ser) 〔Thr) Cys 〔Ty) (Asn (GIn) Ser and thr are a mix of carbon Asn and gln have an chains and hydroxyl functional amide functional group groups( -OH). Cysteine has a thiol group -SH)which is otherwise structurally similar to serine but not chemically similar
polar amino acids - R group consists of carbon, oxygen and nitrogen atoms together they make the sidechain more hydrophilic Asn and Gln have an amide functional group Ser and Thr are a mix of carbon chains and hydroxyl functional groups (-OH). Cysteine has a thiol group (-SH) which is otherwise structurally similar to serine but not chemically similar