Comparison of Trace Elements in High-Molecular-Mass Multiprotein Complex and in Female Milk from Which It Was Obtained

Abstract

Background. Many biological processes are performed by different protein complexes. During the association of proteins and enzymes forming specific complexes, the latter can include ions of various metal ions, which may be important for their formation and biological function. Objective of the Studies. However, to date in the literature there are no data on metal ions that are part of any protein complexes. Methods. A very stable multiprotein complex (~1000±100 kDa) was separated from other proteins of nine samples of female milk by gel filtration on Sepharose 4B. The content of microelements in the stable multiprotein complex and milk was analyzed using two-jet plasma atomic emission spectrometry. Results. The content of different elements in milk on average decreased in the order: Ca>P>Mg>Al≥Zn≥Fe>Cu >B (0.76–3500 μg/g of dry milk powder), while the content of some elements was very low (Sr>Mn>Cr>Ba>Pb>Ag>Ni>Cd, <0.03–0.5 μg/g). The content of eight elements in stable multiprotein complex was 1.2-9.6-fold higher than in milk and increased in the order: Ca≈Mg<P<Al<Fe<Pb<Ba<Cr<Cd<Zn, while content of SPC eight metals was 12.3-110-fold higher: Cu (12.3)>B (19.7)>Ag (28.7)>Ni (38)≥Sr (110). Conclusions. The analysis of the relative content of sixteen elements in human milk and oligomeric complexes of proteins was performed for the first time. Data on the content of metals indicate that during the formation of protein which associates the increase in the content of metal ions bound with proteins of the complex can occur. Such metal ions can be important for the formation and biological function of protein complexes.

Comparison of the Content of Several Elements in Seawater, Sea Cucumber Eupentacta fraudatrix and Its High-Molecular-Mass Multiprotein Complex

“…TJP-AES allows using a small sample to simultaneously estimate the content of about 20 different elements [ 11 , 12 , 13 , 14 , 15 , 16 , 18 ]. Analysis of seawater was carried out after evaporation of water aliquot on graphite powder.…”

“…Using TJP-AES, the mass percent of metal ions in the lyophilized samples of plasma of healthy Wistar rats was estimated: Ca > Mg > Fe > Cu ≥ Zn > Al ≥ Sr > Ti ≥ Mo ≥ Mn ≥ Pb ≥ Co ≥ Ni > Ag [ 17 ]. Blood preparations of Wistar rats were used to purify homogeneous IgGs [ 18 ]. In contrast to plasma preparations, IgGs from Wistar rat plasmas did not contain detectable amounts of Ti, Mo, Si, Cr, or Ag: Fe ≥ Pb ≥ Zn ≥ Cu ≥ Al ≥ Ca ≥ Ni ≥ Mn > Co ≥ Mg [ 17 ].…”

“…In contrast to plasma preparations, IgGs from Wistar rat plasmas did not contain detectable amounts of Ti, Mo, Si, Cr, or Ag: Fe ≥ Pb ≥ Zn ≥ Cu ≥ Al ≥ Ca ≥ Ni ≥ Mn > Co ≥ Mg [ 17 ]. We obtained the milk powders by using fresh mother’s milk and analyzed them using TJP-AES, and their concentrations increased in the following order: Ca > P > Mg > Al > Zn > Fe > Cu > B > Ni ≈ Cr ≈ Ba ≈ Pb > Sr ≈ Cd > Mn > Ag [ 18 ]. Many various biological processes are carried out by protein complexes [ 19 , 20 ].…”

“…At the same time, in the literature, there are no data concerning the possible type of elements and their role in the formation and stabilization of the protein complexes, as well as their role in catalytic activities. TJP-AES was used first to compare the content of different metals in human milk and stable protein complexes from the same milk [ 18 ]. It has been shown that the complex accumulates different metals from milk to varying degrees.…”

“…It has been shown that the complex accumulates different metals from milk to varying degrees. The content of various elements in the protein complex was higher than in milk (-fold): Sr (110.0) > Mn (82.0) > Ni (38.0) > Ag (28.7) > B (19.7) > Cu (12.7) > Zn (9.6) > Cd (9.0) > Cr (6.2) > Ba (5.8) > Pb (4.0) > Fe (3.8) > Al (3.0) > P (2.6) > Ca (1.2) ≈ Mg (1.2) [ 18 ]. It was shown that, in the presence of 8 M urea, the efficiency of the complex dissociation strongly increases after the addition of EDTA.…”