CHAPER 24 AMIINO ACIDS AND PROTEINS 24.1 INTRODUCTION Of the three groups of biopolymers, protein have the most diverse function. Most of its molecular weights are much larger. Their shaps cover a range from the globular protein to the helical coils of a a-keratin. But all proteins have common features Proteins are polyamides and their monomeric units are about 20 different a-amino acids
CHAPER 24 AMINO ACIDS AND PROTEINS 24.1 INTRODUCTION Of the three groups of biopolymers, protein have the most diverse function. Most of its molecular weights are much larger. Their shaps cover a range from the globular protein to the helical coils of a α–keratin. But all proteins have common features. Proteins are polyamides and their monomeric units are about 20 different α-amino acids
Amide links R R R R R R CH CH CH H-N′C-OH CH CH H 0H OH 0 H O An a-amino acid a portion of a protien molecular Primary structure: the exact sequence of the different a-amino acids along the protein chain Second and tertiary structure: the folding of the polyamide chain which give rise to higher levels of complexity Although hydrolysis of natural occurring proteins may yield as many as 22 different amino acids, the amino acids have an important structural feature in common
N H H CH C O OH R N H CH C O R N H CH C O R' N H CH C O R'' N H CH C O R'''' N H CH C O R''' Amide links An -amino acid A portion of a protien molecular Primary structure: the exact sequence of the different α-amino acids along the protein chain. Second and tertiary structure: the folding of the polyamide chain which give rise to higher levels of complexity. Although hydrolysis of natural occurring proteins may yield as many as 22 different amino acids, the amino acids have an important structural feature in common
24.2 AMINO ACIDS 24.2A STRUCTURES AND NAMES CO,H H2N H R AbbrE- NAME VIATION Glycine Gly 6.0 CH3 Alanine Ala 6.0 -CH(CH3)2 Vali Val 6.0 CH2CH(CH3)2 Leucine eu 6.0 CH(CH3 )CH2CH3 norleucine
24.2 AMINO ACIDS 24.2A STRUCTURES AND NAMES H2 N H CO2 H R R NAME ABBREVIATION pI -H -CH3 -CH(CH3 ) 2 -CH2CH(CH3 ) 2 -CH(CH3 )CH2CH3 Glycine Alanine Valine e Leucine e Isoleucine e Gly Ala Val Leu Ile 6.0 6.0 6.0 6.0 6.1
ABBRE R NAMEⅥ Ation pI -HC Pheny lalanine Phe 5.5 CH2 CONH2 Asparagine Asn CHCH CONH Glutamine GI -CH tryptophan° Tr rp 5.9 H HOOC-CH-CH HN、CH Proline Pro (complete structure CH,OH Serine Ser 7
R NAME ABBREVIATION pI H2C -CH2CONH2 -CH2CH2CONH2 N CH2 H Phenylalanine e Asparagine Glutamine Tryptophan e Phe Asn Gln Trp 5.5 5.4 5.7 5.9 HN C H2 CH2 HOOC CH CH2 (complete structure) -CH2OH Proline Serine Pro Ser 6.3 5.7
ABBRE R NAME Ⅵ IATION -CH(CH3 )OH Threonine 6.5 2C OH Tyrosine yr 5.7 HOOCCH-CH, HN、CH Hyroxyproline yp 6.3 (complete structure) CHOSH Cysteine Cys 50 H2 aa- S Cystine ys-cyS CHoCHSCH Methionine Met 5.8 CHCOOH Aspartic acid A 3.0
R NAME ABBREVIATION pI -CH(CH3 )OH H2 C OH HN C H2 CH HOOC CH CH2 (complete structure) OH Threonine e Tyrosine Hyroxyproline Thr Tyr Hyp 6.5 5.7 6.3 -CH2 SH H2 C S S H2 C -CH2 CH2 SCH3 -CH2 COOH Cysteine Cystine Methionine e Aspartic acid Cys Cys-Cys Met Asp 5.0 5.1 5.8 3.0