sâmbătă, 24 noiembrie 2012

AMINO ACIZI NATURALI


 

 

Amino-acizi naturali

 

 

Amino-acizii sunt combinatii organice care contin in molecula una sau mai multe grupe amino si una sau mai multe grupe carboxil. Dupa structura, amino-acizii se impart in doua mari categorii:

1.     Alifatici: unde grupele functionale sunt legate de o catena alifatica, chiar daca in molecula exista un nucleu aromatic.

2.     Aromatici: unde grupele functionale sunt legate de un ciclu aromatic.

 

Dupa asezarea relativa a grupelor functionale se deosebesc α-amino-acizi, β-amino-acizi, γ-amino-acizi, etc. Dintre amino-acizii alifatici, cei mai importanti sunt α-amino-acizi, adica acei amino-acizi care contin grupele functionale legate de acelasi atom de carbon. Se deosebesc mai multe categorii mari de α-amino-acizi alifatici:

1.     monocarboxilici

2.     dicarboxilici

3.     hidroxi-amino-acizi

4.     tioamino-acizi

5.     diamino-acizi

6.     amino-acizi heterociclici

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Denumirea

 
Prescurtarea

 

Formula


 

Amino-acizi  monocarboxilici

 

Leucina

(acidul α-aminoizocapronic)
 
Leu
    CH3—CH—CH2—CH—COOH
                 |                    |
               CH3                 NH2

Izoleucina

(acidul α-amino-β-metilvalerianic)
 

 

Ileu

    CH3—CH2—CH — CH—COOH
                             |         |
                           CH3      NH2

 

Fenilalanina

(acidul α-amino-β-fenil-propionic)
 

 

Fe

 
                    —CH2—CH—COOH
                                     |
                                   NH2

 

Glicocolul(glicina)

(acidul aminoacetic)
 
 
Gli
    CH2— COOH
       |
     NH2
 
Alanina
(acidul α-aminopropionic)
 
Ala
    CH3—CH—COOH
                  |
                NH2
 

Valina

(acidul α-aminoizovalerianic)
 
Val
     CH3—CH — CH—COOH
                  |         |
                CH3       NH2

 

 

 

Amino-acizi dicarboxilici

 

Acidul asparagic

(acidul aminosuccinic)
 
Asp

     HOOC—CH2—CH—COOH

                                    |
                                  NH2
Acidul glutamic
(acidul α-aminoglutaric)
 
Glu
     HOOC—CH2— CH2—CH—COOH
                                               |
                                             NH2

 

 


Hidroxi-amino-acizi


 

Treonina
(acidul α-amino-β-hidroxibutiric)
 
Tr
    CH3—CH — CH—COOH
                 |           |
                OH      NH2
 
Tirosina
(acidul α-amino-β-hidroxifenil-propionic)
 
Ti
  
    HO                    —CH2—CH—COOH
                                               |
                                             NH2
Serina
(acidul α-amino-β-hidroxipropionic)
 
Ser

     CH2 — CH—COOH

       |         |
      OH     NH2

 

Tio-amino-acizi


 

Cistina

(acidul di[α-amino-β-tiopropionic] )
Ci—S
Ci—S

HOOC—CH—CH2—S—S-- CH2—CH—COOH

                      |                                           |
                 NH2                                     NH2
 
Metionina
(acidul α-amino-γ-metiltiobutiric)
 
Met
 CH2 CH2—CH—COOH
   |                     |
    S -- CH3          NH2

 

Cisteina

(acidul α-amino-β-tiopropionic)

 

Cis

     CH2 — CH—COOH

       |          |

      SH      NH2


 


 


Diamino-acizi


 

Ornitina
(acidul α, δ-diaminovalerianic)
 
Or
   CH2 CH2CH2—CH—COOH
     |                                |
   NH2                                        NH2

Lisina

(acidul α, ε-diaminocapronic)
 
Lis
   CH2 CH2CH2—CH2—CH—COOH
    |                                            |
  NH2                                                         NH2

 

Amino-acizi heterociclici


 

 
Prolina
(acidul pirolidin-α-carboxilic)
 
 
Pro
                         H2C CH2 
                           |         |
                         H2C      CH—COOH
                             \       /
                                NH

 

Hidroxiprolina

(acidul β-hidroxipirolidin-α-carboxilic)
 
 
Hipro

              HO—HC — CH2

                               |           |
                        H2C      CH—COOH
                            \       /
                               NH
 
Histidina
(acidul α-amino-β-imidazolil-(4)-propionic)
(imidazolil-(4)-alanina)
 
 
His

        N — C — CH2— CH—COOH

         ||       ||                        |
       HC     CH                NH2
          \       /
             NH
 
Triptofanul
(acidul α-amino-β-indolil-(3)-propionic)
(indolil-(3)-alanina)
 
 
Tri
                                 
                          CH2CH—COOH
                                             |
                                           NH2