ANALYSIS AND CALCULATIONS OF THERMODYNAMIC FUNCTIONS OF AMINO ACIDS AND CARBOHYDRATES

 

Vitaly Ovchinnikov

 

A.N. Tupolev Kazan national researching technical university.                                                                             Kazan 420111, K.Marx str.10, Tel/Fax +7(843)2310261; e-mail: chem_vvo@mail.ru

 

        Thermodynamic characteristics of such amino acids as glycine (I, C2H5NO2), L-alanine (II, Ñ3Í7NÎ2), D,L-ornitine (III, C5H12N2O2), L-leucine (IV, C6H13NO2), N-D,L-leucyl-glycine (V, C5H9NO2), L-tyrosine (VI, C9H11NO3) are known in literature [1]. We founded that their thermodynamic functions (Dc,f,s,cpΨo) free energy of combustion  (∆cGo), heats of combustion (∆cHo) and  formation (∆fHo), entropy(So) and heat capacity (Cp) dependent from the number (N) of valence electrons except for a number (h) of a lone electron pairs (g) of heteroatoms in amino acids (Eq. 1). This circumstance allow us after analysis of thermodynamic functions of amino acids (I-VI) [2] to calculate the equations (2-5).

Dvap,c,f,sΨo = i ± f *(N - hg)                                                                         (1).

∆cGo = (77.8±33.2) – (107.6±1.1) (N-hg); r 0.999, So 28.3, n   4              (2)

∆cHo = (99.8±51.2) – (106.8±0.6) (N-hg);  r 0.999, So 49.4, n  6               (3)

∆fHo = (-445.3±98.2) – (7.3±3.1) (N-hg);   r 0.860, So 93.5, n  4               (4)

    So  = (52.0±32.5) + (4.6±1.1) (N-hg);     r  0.923, So 30.3,n   5              (5)

        Thermodynamic parameres of the majority of sugars are known now also. Earlier it was informed [1] on the sizes of free energy of combustion (∆cGo) and formations (∆fGo) in the standard conditions α-D-galactose (VII, Ñ6Í12Î6), α-D-glucose (VIII, Ñ6Í12Î6), α-D-lactose (IX, Ñ12Í22Î11), α-D-sacharose (X, Ñ12Í22Î11) and D-fructose (XI, Ñ6Í12Î6) (Table 1). Also it has been shown [3], that heat of combustion (∆cHî) the majority of organic connections including sugars, can be calculated on the equation (1).

       In view of it, the equations (6-9), specifying that circumstance, have been calculated, that not only heat of combustion, but also free energy of combustion and formation processes, entropy (Sî) and the heat capacity (Ñð) of sugars [3] are characterized by the similar excellent dependences, connecting them with parameter (N - hg) too.

∆Gocomb = (66.7±2.1) – (122.4±0.6) (N-hg);     r 0.999, So 15.3, n 5          (6)

∆Gof          = (-303.9±20.8) – (25.6±0.6) (N-hg); r 0.999, So 15.3, n 5          (7)

   So       = (22.2±4.6) + (7.8±0.1) (N-hg);        r 0.999, So 2.7,   n 3           (8)

   Cp       =  (19.6±16.2) + (8.4±0.4) (N-hg);     r 0.996, So 11.9, n 5           (9)

 

Table 1. Thermodynamic functions (kJ mol-1and J mol-1 K-1) amino acids and carbohydrates in condensed phase at 298.15 K

No of compounds, (N – hg)

 

-∆cGo

 

-∆fGo

 

-∆cHo

 

-∆fHo

 

So

 

Cp

1

2

3

4

5

6

7

Amino acids

I, 10

1008.3

373.5

975.0

527.5

103.5

 

II, 16

1642.0

371.3

1621.4

559.5

129.2

 

III, 30

2916.5

 

3029.9

 

178.9

 

IV, 34

3551.3

 

3572.0

 

164.1

 

V, 44

 

 

4574.8

859.9

281.2

 

VI, 42

4466.8

 

4428.1

658.6

 

 

Carbohydrates

VII, 24

2865.9

923.5

2804.5

1271.5

205.4

217.0

VIII, 24

2872.2

917.2

2803.3

1272.8

209.2

235.9

 

Table 1 (continued)

1

2

3

4

5

6

7

IX, 48

5826.5

1515.2

5629.5

2214.2

 

417.6

X, 48

5789.9

1551.8

5643.4

2221.2

392.4

424.3

XI, 24

2874.1

915.4

2809.8

1266.2

 

208.0

 

References

 

[1]    Metzler D.  Biochemistry.  Mir, Moscow. (1980) 407 p.                                                                                    

[2]    Ovchinnikov V.V..  American J. Phys. Chem. (2013),  1, 8-15.                                                                          [3]    Ovchinnikov V.V. Chem. Journal, (2013) 02, 59-65.