Table 5. Comparative Data Showing Chemical Reactivity Descriptors of Alanine, Threonine, Glutamic Acid, and Lysine Amino Acids.

structural parameters	alanine	threonine	glutamic acid	lysine
total energy (kcal/mol)	–30659.19	–41644.40	–51997.75	–46530.97
heat of formation (kcal/mol)	–104.75	–153.99	–201.17	–120.39
binding energy (kcal/mol)	–1214.25	–1598.14	–1875.77	–2220.27
EHOMO (eV)	–10.32	–10.21	–10.53	–9.74
ELUMO (eV)	0.94	0.91	0.67	0.91
ionization energy [IE (−εHOMO)]	10.32	10.21	10.53	9.74
electron affinity [EA (−εLUMO)]	1-0.94	–0.91	–0.67	–0.91
band gap (eV) [EHOMO - ELUMO]	–11.26	–11.11	–11.20	–10.65
electronegativity (eV) χ [(IE + EA)/2	4.69	4.65	4.93	4.41
chemical potential μ (−χ)	–4.69	–4.65	–4.93	–4.41
chemical hardness (eV) η [(IE– EA)/2]	5.63	5.55	5.6	5.31
chemical Softness (eV) σ (1/η)	0.177	0.180	0.178	0.188
electrophilicity Index Ω (μ2/2η)	1.95	1.94	2.17	1.83