Download amino acids(郑锦鸿)

Ⅳ. Chemical Properties
R
carboxyl,羧基
CH COOH
NH2
amino, 氨
基
1. Acidity
R
CH COOH
NH2
NaHCO3
R
CH COONa + CO2
NH2
1
R
CH COOH
Na2CO3
R
NH2
NH2
R
CH COOH
NH2
CH COONa + CO2
NaOH
R
CH COONa
NH2
2
HOOC CH2CH2CH COOH 1mol NaOH HOOC CH2CH2CH COONa
NH2
glutamic acid, 谷氨酸
NH2
monosodium glutamate
谷氨酸单钠盐
(gourmet powder)
味精
3
Chinese restaurant syndrome (CRS), 中国餐馆综合征
Kwok, R.H.M. Chinese Restaurant Syndrome. New
England Journal of Medicine, 1968, 17:796.
Headache was most commonly reported, also dizziness
(头晕), diarrhea (腹泻), nausea (恶心), and stomach
cramps (胃痉挛). . . .
4
1983, Adults:  8g/d, Children (< 12 years old): No
1987, Adults:  No limitation, Children : Yes

Neurotoxicity

Allergies

Sensitivities
~1%
5
2. Basicity
R CH COOH
NH2
HCl
R CH COOH
NH2 HCl
6
3. Amphoteric ionization
R
CH COOH
NH2
R
CH COO
NH3
zwitterion (inner salt)
两性离子（内盐）
Amino acids are ionic compounds under normal condition.
High melting point
Miscible with water, but quite insoluble in typical
nonpolar organic solvents
7
4. Deamination
R
CH COOH
NH2
[O]
R
C COOH
NH
Enamine, 烯胺
H2O
R
C COOH
O
Keto acid, 酮酸
8
苯丙氨酸羟化酶
phenylalaninase
phenylalaninase
HO
HO
CH22CHCOOH
CHCOOH
CH
NH22
NH
Tyrosine, 酪氨酸
CH22CHCOOH
CHCOOH
CH
NH22
NH
Phenylalanine
苯丙氨酸
[O],HH22OO
[O],
CH22CCOOH
CCOOH
CH
OO
Phenylpyruvic acid
苯丙酮酸
9
Phenylketonuria (苯丙酮酸尿症)
Not sufficient Phenylalanine from diet; tyrosine becomes
conditionally essential.
10