A Study of Cobalamin Complexes with some Amino Acids

Abstract

The aimof this study was to preparecobalamin and amino acids complexes to investigate the possibility of designing a drug and study its biological and chemical activity (behaviour). The study also was aimed to propose the appropriate conditions for complex formation. The experiments were carried by replacing water molecules asweak ligands ligand in the upper part (β) of the cobalamin by amino acids. Two types of amino acids with different donor atoms were used: alanine and cysteine. All solutions were prepared and placed in a water path at 40 Cfor one hour and the pH was measured. The pH of aquacobalamin was found to be 5.4 . The pH of alanine-cobalamin complex and cysteine-cobalamin complex was adjusted at pH=2 and pH=12.4) . the (UV-vis) spectrum of resulting solutions was recorded at rang of 200-800 nm,the spectrum showed that alanine-cobalamin complex which prepared in acidic medium gave small change compared to aqua cobalamin but the complex which prepared in alkaline medium did not show a change, while the cysteine-cobalamin complex at pH =12.4 showed a clear change . The optical activity (α) was determined by a Polarimeter . The aquacobalamin and Alanine-cobalamin complex at pH=2 gavevalue with positive sign (+ 0.057 and + 0.031 respectively),while cysteine-cobalamin complex at pH =12.4 gave a negative value (- 0.100) .