role of Metal Ion in Inorganic Biochemistry

摘要

Inorganic biochemistry is an emerging subject and interdisciplinary field between inorganic chemistry and biochemistry. It began to be as an independent subject since the establishment of international issue, Journal of Inorganic Biochemistry, and developed gradually in recent forty years. Inorganic biochemistry has fascinated the scientists' attention and is a very active field among nature science. The task of inorganic biochemistiy is to research the interaction between the metal complex (or metal ion) with biological ligand at the molecular level. There exists wide research about inorganic biochemistry such as biological macromolecular, oxygen carrier, hemoglobin, mimic enzyme, DNA-binding and cytotoxicity, biological mineralization, etc. Encompassing the varied and disparate roles of metal ions in biology, the field of bioinorganic chemistry has reached a certain level of maturity, hi this review, the role of metal ion in inorganic biochemistry is discussed in detail and it covers the interaction of metal complex with biological molecular, DNA-binding mode and biological activity, the binding to the membrane molecules (human erythrocyte membrane) and the functions of metal complex in biological hydrolysis process. Researching fields are as follows: 1) the interaction of metal complex with biological molecular (DNA and a-amino acid): The metal complex maybe interact with calf thymus DNA by intercalative and coordination binding mode. Additionally, the contribution from the electrostatic interaction between DNA and aliphatic side chain moiety in the metal complex cannot be ignored. The longer the aliphatic side chain is, the stronger the electrostatic interaction is. However, the Pt/Pd complexes may interact with DNA by non-intercalation. It has been found that linear free energy relationships, linear enthalpy relationships and linear entropy relationships exist in the system containing metal ion and biological small molecules for example a-amino acid; 2) biological acitivity: Some Pt~(2+)/Pd~(2+) complexes exhibit significant cytotoxicity against cancer cell lines and the pyridine ring moiety coordinated with Pt~(2+)/Pd~(2+) play an important role in its antitumor activities. Additionally, Ln~(2+) complexes containing amino acid moiety with nonpolar aliphatic side chains show interesting antitumor activity in vitro against different cell lines. Moreover, the cytotoxic properties of Ln~(2+) complexes seem to increase gradually as the lipophilicity of nonpolar aliphatic side chains increase; 3) the effect of metal ions to hemoglobin (Hb): Rare earth metal ions binding to the membrane molecules (human erythrocyte membrane) induce the phase transition of lipid bilayer, conformational changes and aggregation of membrane proteins; 4) metalloenzyme catalysis: metal complexes are more efficient catalyst hydrolysis of ATP, NPP, HPNP, NA, CA, and etc biological small molecules than protonated ligand at a certain pH range. The water molecule (or -OH) participates in the catalytic hydrolysis of biological small molecule in different steps with different functions.