氨基酸(Amino Acids) (20 standard amino acids 2.Aromatic R groups (3) COO cOO +H3N- 一H +H3N-H +H3N- H CH2 CH2 CH2 OH Phenylalanine (Phe) Tyrosine(Tyr) Tryptophan(Try) 苯丙氨酸 酪氨酸 色氨酸 UV特征吸收：入=280nm
一、氨基酸 (Amino Acids) （二）20 standard amino acids UV 特征吸收：l = 280 nm +H3N COO - H CH2 +H3N COO - H CH2 +H3N COO - H CH2 Phenylalanine (Phe) Tyrosine (Tyr) Tryptophan (Try) 苯丙氨酸 酪氨酸 色氨酸 2. Aromatic R groups (3) N H OH
(20 standard amino acids 3.Polar,uncharged R groups(6) COO- C00 C00 +H3N-H *H3N-H *HgN-H CH>OH CHOH CH3 CH2SH Serine(Ser) Threonine (Thr) Cysteine(Cys) 丝氨酸 苏氨酸 半胱氨酸 C00 C00 cOO- +H3N- 一H +H3N- H +H3N- -H CH2 CH2 CH2SCH3 CONH2 CONH2 Methionine(Met) Asparagine (Asn) Glutamine(GIn) 甲硫氨酸（蛋氨酸) 门冬酰胺 谷氨酰胺
（二）20 standard amino acids +H3N COO - H CH2OH +H3N COO - H CHOH +H3N COO - H CH2SH +H3N COO - H CH2 +H3N COO - H CH2 CH2SCH3 CONH2 Serine (Ser) Threonine (Thr) Cysteine (Cys) Methionine (Met) Asparagine (Asn) Glutamine (Gln) 丝氨酸 苏氨酸 半胱氨酸 甲硫氨酸（蛋氨酸） 门冬酰胺 谷氨酰胺 3. Polar, uncharged R groups (6) CH3 +H3N COO - H CH2 CH2 CONH2
、Amino Acids (20 standard amino acids 4.Negatively charged R groups (2) COO COO +H3N-H +H3N- 一H CH2 CH2 coo CH2 COO Aspartate (Asp) Glutamate(Glu) 门冬氨酸 谷氨酸 Acidic amino acids containing two carboxylic groups
一、Amino Acids （二）20 standard amino acids Acidic amino acids——containing two carboxylic groups +H3N COO - H CH2 COO - Aspartate (Asp) Glutamate(Glu) 门冬氨酸 谷氨酸 +H3N COO - H CH2 CH2 COO - 4. Negatively charged R groups (2)
()20 standard amino acids 5.Positively charged R groups (3) C00 C00 +H3N H *H3N- }H cOO C 洲 +H3N-H z H2C NH imidazole guanidino -NHZ HN~ NH NH2 Lysine (Lys) Arginine (Arg) Histidine 赖氨酸 精氨酸 组氨酸 Basic amino acids- containing two amino groups
（二）20 standard amino acids Basic amino acids —— containing two amino groups +H3N COO - H CH2 CH2 Lysine (Lys) Arginine (Arg) 赖氨酸 精氨酸 +H3N COO - H CH2 CH2 CH2 5. Positively charged R groups (3) CH2 CH2 NH3 + NH C NH2 NH2 + +H3N COO - H H2C HN guanidino NH imidazole Histidine 组氨酸
Essential amino acids The amino acids that must obtain from our diets because/we either /cannot synthesize them/at all or cannot synthesize them in adequate amounts o 10 essential amino acids: Val,Leu,lle,Thr,Met,Lys,Arg,Phe, Try,His
Essential amino acids ⚫ The amino acids that must obtain from our diets because we either cannot synthesize them at all or cannot synthesize them in adequate amounts ⚫ 10 essential amino acids: Val, Leu, Ile, Thr, Met, Lys, Arg, Phe, Try, His