Hubungan Pola Konsumsi Makanan Sumber Zat Besi Heme dan Non Heme, Protein, Vitamin C dengan Kejadian Anemia Gizi pada Remaja Putri di Kabupaten Majene

Anemia merupakan kelainan gizi yang paling sering ditemukan di dunia dan menjadi masalah kesehatan masyarakat yang bersifat epidemik. Salah satu golongan yang rawan terkena anemia adalah remaja. Penelitian ini bertujuan untuk mengetahui hubungan antara pola konsumsi makanan sumber zat besi heme dan non heme, protein, vitamin c dengan kejadian anemia pada remaja putri di Kabupaten Majene. Jenis penelitian yang digunakan adalah kuantitatif deskriptif dengan menggunakan desain cross-sectional. Sampel berjumalah 126 orang. Data diperoleh menggunakan kuesioner ffq dan pengambilan sampel darah. Analisis data di dilakukan secara univariat dan bivariat menggunakan uji chi square. Hasil analisis uji chi-square dengan α=0,05, menunjukkan tidak ada hubungan bermakna antara pola konsumsi makanan sumber zat besi heme dengan kejadian anemia pada remaja putri (p=0,340), tidak ada hubungan antara pola konsumsi makanan sumber zat besi non heme dengan kejadian anemia pada remaja putri (p=0,981), tidak ada hubungan antara pola konsumsi makanan sumber protein dengan kejadian anemia pada remaja putri (p=0,674), tidak ada hubungan antara pola konsumsi makanan sumber vitamin c dengan kejadian anemia pada remaja putri (p=0,354), tidak ada hubungan antara pola konsumsi makanan sumber penghambat zat besi dengan kejadian anemia pada remaja putri (p=0,734), dan ada hubungan antara haid/menstruasi dengan kejadian anemia pada remaja putri (p=0,008). Dari penelitian ini dapat disimpulkan tidak ada hubungan antara pola konsumsi makanan sumber zat besi heme, non heme, protein, vitamin c serta penghambat penyerapan zat besi dengan kejadian anemia pada remaja putrid an ada hubungan antara haid/mentruasi dengan kejadian anemia pada remaja putri di Kabupaten Majene.

Synthetic heme protein models that function in aqueous solution

Supramolecular porphyrin–cyclodextrin complexes act as biomimetic heme protein models in aqueous solution.

Structural Insights into the Heme Pocket and Oligomeric State of Non-Symbiotic Hemoglobins from Arabidopsis thaliana

Non-symbiotic hemoglobins AHb1 and AHb2 from Arabidopsis thaliana are hexacoordinate heme-proteins that likely have different biological roles, in view of diverse tissue localization, expression pattern, and ligand binding properties. Herein, we expand upon previous biophysical studies on these isoforms, focusing on their oligomeric states and circular dichroism (CD) characteristics. We found that AHb1 exists in solution in a concentration-dependent monomer-dimer equilibrium, while AHb2 is present only as a monomer. The quaternary structure of AHb1 affects its degree of hexacoordination with the formation of the dimer that enhances pentacoordination. Accordingly, the mutant of a conserved residue within the dimeric interface, AHb1-T45A, which is mostly monomeric in solution, has an equilibrium that is shifted toward a hexacoordinate form compared to the wild-type protein. CD studies further support differences in the globin’s structure and heme moiety. The Soret CD spectra for AHb2 are opposite in sense to those for AHb1, reflecting different patterns of heme-protein side chain contacts in the two proteins. Moreover, the smaller contribution of the heme to the near-UV CD in AHb2 compared to AHb1 suggests a weaker heme-protein association in AHb2. Our data corroborate the structural diversity of AHb1 and AHb2 and confirm the leghemoglobin-like structural properties of AHb2.

X-ray–induced photoreduction of heme metal centers rapidly induces active-site perturbations in a protein-independent manner

Since the advent of protein crystallography, atomic-level macromolecular structures have provided a basis to understand biological function. Enzymologists use detailed structural insights on ligand coordination, interatomic distances, and positioning of catalytic amino acids to rationalize the underlying electronic reaction mechanisms. Often the proteins in question catalyze redox reactions using metal cofactors that are explicitly intertwined with their function. In these cases, the exact nature of the coordination sphere and the oxidation state of the metal is of utmost importance. Unfortunately, the redox-active nature of metal cofactors makes them especially susceptible to photoreduction, meaning that information obtained by photoreducing X-ray sources about the environment of the cofactor is the least trustworthy part of the structure. In this work we directly compare the kinetics of photoreduction of six different heme protein crystal species by X-ray radiation. We show that a dose of ∼40 kilograys already yields 50% ferrous iron in a heme protein crystal. We also demonstrate that the kinetics of photoreduction are completely independent from variables unique to the different samples tested. The photoreduction-induced structural rearrangements around the metal cofactors have to be considered when biochemical data of ferric proteins are rationalized by constraints derived from crystal structures of reduced enzymes.