T e m a

GLUCIDELE

(HIDRAŢII DE CARBON).

MONOZAHARIDELE.

C

O

H

C H O H ) n

C H 2 O H

(

CH2OH

C=O

CHOH)n(

CH2OH

Aldoze ( n = 1,2,3…) Cetoze ( n = 1,2,3… )

Stereoizomeria monozaharidelor

C

O

H

CH2OH

OH

H

H

H

HO

HO

HHOH OH

C

O

H

CH2OH

OH

OH

HHO

H

H

D - Glucoza L - Glucoza

Pentozele

C

CH2

CH2OH

OHH

OHH

O

HC

CH2OH

OHH

OHH

O

H

HHO

C

CH2OH

OHH

OHH

O

H

HHO

C

CH2OH

OHH

OHH

OHH

O

H

D-Riboza D-Xiloza D-Arabinoza D-Dezoxiriboza

Hexozele

C

OHH

OHH

O

H

HHO

CH2OH

OHH

C

O

H

CH2OH

OHH

C

OHH

O

H

CH2OH

OHH

HHO

HHO

OHH

CH2OH

C=O

CH2OH

OHH

HHO

HHO

HHO

OHH

D-Glucoza D-Manoza D-Galactoza D-Fructoza

C

H

OHH

O

H

HHO

CH2OH

OHH

NH2

C

O

H

CH2OH

OHH

HHO

HHO

H NH2

D-Glucozamina D-Galactozamina

Tautomeria oxo-ciclică a monozaharidelor

C

H

OHH

O

H

HHO

CH2OH

OHH

OH

C

H

OHH

H

HHO

CH2OH

H

OH

HO

O

C

H

OHH

HHO

CH2OH

H

OH

O

OHH

β-D-Glucoza D-Glucoza α-D-Glucoza

O O

Ciclu piranozic Ciclu furanozic

C

H

O

H

OH

HHO

OHH

CH2OH

OHH

O

CH2OH

HH

OH

H

H

OH

H

OHO

O

CH2OH

HH

OH

H

H

OH

OH

HOH H

α-D-Glucopiranoza D-Glucoza β-D-Glucopiranoza

C

H OH

H OH

H OH

CH2OH

O H

O H

OHH

OH

H

OH

C

H

HO H2 H2HO O OH

HH

OH

H

OH

C

H

α-D-Ribofuranoza D- Riboza β-D-Ribofuranoza

OHH

CH2OH

OHH

HHO

C=O

CH2OHOCH2

H H

OH

O

H

CH2OH

OH

HO

H H

HO OCH2

H H

OH

O

H

OH

CH2OH

α-D-Fructofuranoza D-Fructoza β-D - Fructofuranoza

O

H

H

OH

H

H

OH

H

HO

HOCH2OH CH2OH

O

H

HH

H

OH

HO

HO

H

OH

α-D-Glucopiranoza β-D- Glucopiranoza

Proprietățile chimice ale monozaharidelor

1.Formarea și hidroliza glicozidelor

O

CH2OH

HH

OH

H

H

OH

H

OHOH

HO CH3+HCl

O

CH2OH

HH

OH

H

H

OH

H

O O CH3

+ H2O(c)

α-D-Glucopiranoza O-Metil-α-D-glucopiranozidă

O

CH2OH

HH

OH

H

H

OH

H

OHOH

O

CH2OH

HH

OH

H

H

OH

H

O O CH3

+ H2OH+

+ CH3OH

H

O-Metil-α-D-glucopiranozidă α-D-glucopiranoza

2. Formarea și hidroliza eterilor

α-D-Glucopiranoza О-Metil-2,3,4,6-α-D-tetrametil-

glucopiranozidă

O

HH

H

H

H

O CH3

CH2OCH3

OOCH3

OCH3

+ H2OH+

+ CH3OH

CH3

O

HH

H

H

H

CH2OCH3

OOCH3

OCH3

OHCH3

О-Metil-2,3,4,6-tetrametil- 2,3,4,6-Tetrametil- α-D-

α-D-glucopiranozidă glucopiranoza

+ H2OO4S+ Na2NaOH

CH3

+ (CH3)SO4

O

HH

H

H

H

O CH3

CH2OCH3

OOCH3

OCH3

O

CH2OH

HH

OH

H

H

OH

H

OHOH2

3. Formarea și hidroliza esterilor

+ 5 CH3COOH

CH3OC

O

HH

H

H

H

CH2OCOCH3

O

OCOCH3

OCOCH3

OCOCH3

+ 5 (CH3CO)2O

H

O

CH2OH

HH

OH

H

H

OH

H

OHO

α-D-Glucopiranoza Pentaacetil-α-D-glucopiranoza

+H2O (H )+ 5 CH3COOH

CH3OC

O

HH

H

H

H

CH2OCOCH3

O

OCOCH3

OCOCH3

OCOCH3

H

O

CH2OH

HH

OH

H

H

OH

H

OHO

Pentaacetil-α-D-glucopiranoza α-D-Glucopiranoza

6-Fosfat de glucoză 6-Fosfat de fructoză

1,6-Difosfat de fructoză

Fosfați de monozaharide

O

CH2O

HH

HOOH

H

H

OH

H

OH

PO3H2

O

CH2OPO3H2

OH

O

CH2OH

H

O

CH2OPO3H2

OH

O

CH2OPO3H2

H

O

O

OH

OH

OH

CH2OH

H

ATP ADP

Hexochinaza

O

O

OH

OH

OH

CH2OPO3H2

H

Mg2+

Glucopiranoza Glucopiranozo-6-fosfat

O

O

OH

OH

OH

CH2OPO3H2

H Glucozo - 6 - fosfatizomeraza

O

CH2OPO3H2

OH

O

CH2OH

H

Glucopiranozo-6-fosfat Ffructozo-6-fosfat

ATP ADP

Mg2+

O

CH2OPO3H2

OH

O

CH2OH

H

O

CH2OPO3H2

OH

O

CH2OPO3H2

H

6 - Fosfatfructokinaza

Ffructozo-6-fosfat Ffructozo-1,6-difosfat

Oxidarea și reducerea monozaharidelor

De exemplu, oxidarea glucozei:

OHH

CH2OH

OHH

C

H

O

H

OH

HHO

OHH

CH2OH

OHH

C

H

O

OH

HHO

OH

Br2 (H2O)

D - Glucoza Acidul-D-gluconic

OHH

CH2OH

OHH

C

H

O

H

OH

HHO

OHH

OHH

COOH

HNO3 (p)

H OH

HHO

COOH

D - Glucoza Acidul-D-glucaric

OHH

CH2OH

OHH

C

H

O

H

OH

HHO

OHH

OHH

COOH

H OH

HHO

H

O

HH

OH

H

H

OH

OH

HO

COOHC

O

H

О - enzimă

D -Glucoza Acidul-D-glucuronic

Reducerea monozaharidelor:

C

H

O

H

OH

HHO

OHH

CH2OH

OHH

OHH

CH2OH

OHH

H OH

HHO

CH2OH

NaBH4

D - Glucoza D - Sorbitol

Schema sintezei acidului ascorbic:

OHH

CH2OH

OHH

H OH

HHO

CH2OH

C=O

CH2OH

HHO

OHH

CH2OH

HHO

OHH

CH2OH

HHO

C=O

HHO

COOH

H

CH2OH

HHO

C=O

HHO

C

O

O

O O

D-Sorbitol L-Sorboza Acidul-2-oxo-L-gulonic γ-Lactona

(Vit.С)

H

CH2OH

HHO

C

O

O

C

C OH

OH

O

O

OH

CH(OH)CH2OH

H

HO

Acidul-L-ascorbic (Vit.С ) .

O

OHHO

O CH CH2

OH

OHO

H

OO CH CH2

OH

OH

O O

Acidul ascorbic Acidul dehidroascorbic

+

CH3CONH

O

H

CHOH

HH

OH

H

H

COOH

OH

CHOH

CH2OH

OHH

CH2OH

OHH

H

HCH3CONH

OHH

CH2

C

COOH

O

OH

OHH

CH2OH

OHH

HHO

HCH3CONH

OHH

CH2

C

COOH

O

COOH

C

CH3

O

C

OHH

O

H

CH2OH

OHH

HHO

HCH3CONH

N-Acetilmanozamina Acidul neuraminic