第十六章 氨基酸、肽和蛋白质 Amino Acids,Peptides and Protein
第十六章 氨基酸、肽和蛋白质 Amino Acids, Peptides and Protein
本章主要内容 氨基酸(Amino Acid(重点内容) (一)结构特点 (二)20种基本氨基酸 (三)氨基酸的特性 二、肽Peptides) 三、 蛋白质Proteins)(简述)
本章主要内容 一、氨基酸 (Amino Acid)（重点内容） （一）结构特点 （二）20 种基本氨基酸 （三）氨基酸的特性 二、肽 (Peptides) 三、蛋白质 (Proteins)（简述）
、Amino Acid ·分子中既含有氨基，又含有羧基的化合 物统称为氨基酸。 COOH CH3CHCOOH NH>CH>CH>COOH NH2CH2CH2CH2COOH .NH2 NH2 @-amino acid Bamino acid amino acid o-amino benzoic acid 组成肽和蛋白质的结构单元分子 a-amino Acid
一、Amino Acid ⚫ 分子中既含有氨基，又含有羧基的化合 物统称为氨基酸。 ⚫ 组成肽和蛋白质的结构单元分子 —— a- amino Acid CH3CHCOOH COOH NH2 NH2 NH2CH2CH2COOH NH2CH2CH2CH2COOH a-amino acid -amino acid -amino acid o-amino benzoic acid
-、Amino Acids (一)Configuration COOH COOH H2N-H H-NH2 R R L-@-amino acid D-@-amino acid When R#H,a-C is a chiral carbon,there are two stereoisomers (D and L-a-amino acid) The amino acids in protein molecules are the L-a-amino acids. 20 standard amino acids in proteins
一、Amino Acids （一）Configuration • When R ≠ H, a-C is a chiral carbon, there are two stereoisomers (D and L- a- amino acid) • The amino acids in protein molecules are the L- a - amino acids. • 20 standard amino acids in proteins H2N H COOH R H NH2 COOH R L-a-amino acid D-a-amino acid
(20 standard amino acids 1.Nonpolar,aliphalic R groups(6) COO CoO COO *H3N-H +H3N-H +HgN-H H CH3 CH(CH3)2 Glycine(Gly) Alanine (Ala) Valine (Val) 甘氨酸 丙氨酸 缬氨酸 COO C00 * +H3N- 一H +H3N- H 肽链的 CHiCHz CH(CH3) +H2N CH2CH3 Leucine (Leu) Isoleucine (Ile) 架变化 Proline (Pro) 亮氨酸 异亮氨酸 脯氨酸
（二）20 standard amino acids +H3N COO - H +H2N COO - H +H3N COO - H CH3 +H3N COO - H CH(CH3 )2 +H3N COO - H CH2 +H3N COO - H CH(CH3 ) CH(CH3 )2 CH2CH3 Glycine (Gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile) Proline (Pro) 甘氨酸 丙氨酸 缬氨酸 亮氨酸 异亮氨酸 脯氨酸 1. Nonpolar, aliphalic R groups (6) * 肽 链 的 骨 架 变 化
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