Mechano‐chemical Synthesis and Spectroscopic Characterization of Hemin Complexes with Some Amino Acids

Abstract

The mechano-chemical reactions of hemin with arginine (Arg), histidine (His), lysine (Lys), methionine (Met) and tryptophan (Trp) were monitored using IR and Mössbauer spectroscopies. According to IR spectra, with exception of Arg, these basic amino acids don´t react at the peripheral propionic acid groups of hemin which is related with their relatively low basicity. Arg also forms a penta-coordinated complex with hemin at the iron site, as revealed by the Mössbauer spectra of the hemin -Arg milled mixtures. The hemin -Arg solid state reaction is completed in 1:3 molar ratio suggesting that this is the stoichiometry of

The putative heme transporter HCP1 is expressed in cultured astrocytes and contributes to the uptake of hemin

“…One potential concern regarding the use of serum-free medium in this study is the solubility of hemin, because hemin tends to form aggregates in the absence of heme-binding proteins. However, the presence of arginine (0.40 mM) within DMEM helped to maintain the solubility of hemin by preventing the formation of aggregates, thus allowing cells to accumulate hemin in serum-free medium (Paneque et al, 2003). Another concern regarding the use of serum-free medium is the potential for hemin to be nonspecifically adsorbed onto the cell membrane.…”