Spectroscopic and binding studies on the interaction of inorganic anions with lactoperoxidase

Crystal Structure of Lactoperoxidase at 2.4 Å Resolution

“…The catalytic mechanism involving peroxidases is complex, and the preference for the substrates is based on a number of properties. 5,30,31 More crystallographic information for various peroxidase-substrate complexes will be helpful for further understanding of the intricate mechanism.…”

Thiocyanate Modulates the Catalytic Activity of Mammalian Peroxidases

“…Recent x-ray crystal structure analysis and a variety of spectroscopic measurements have shown that SCN Ϫ binding occurs at distal heme cavity and serves as either a substrate or inhibitor, causing a diverse impact on the catalytic characteristic behavior of mammalian peroxidases and function (16, 28 -30, 38, 39). In some cases, these co-substrates bind to the peroxidase heme iron and form the corresponding low spin, sixcoordinate complex that inhibits the catalytic activity of the enzyme (45).…”

“…However, the presence of higher levels of SCN Ϫ (e.g. Ͼ1 mM) may promote the formation of such a complex (45). Formation of E-Fe(III)-SCN can be characterized based on its distinctive absorbance feature, which displays a large red shift in the Soret absorbance region compared with native enzyme (45).…”

“…Ͼ1 mM) may promote the formation of such a complex (45). Formation of E-Fe(III)-SCN can be characterized based on its distinctive absorbance feature, which displays a large red shift in the Soret absorbance region compared with native enzyme (45). Whether the slow binding of H 2 O 2 to the enzyme occurs through conformational changes in the heme pocket geometry or because of the replacement reaction, the rate-limiting step becomes the binding of H 2 O 2 to the enzymes.…”

Disruption of the Aspartate to Heme Ester Linkage in Human Myeloperoxidase

“…In addition, the halogenation activity of recMPO and the Asp 94 variants was measured by continuously monitoring hydrogen peroxide concentration polarographically with a platinum electrode covered with a hydrophilic membrane and fitted to the Amperometric Biosensor Detector 3001 (Universal of the various enzyme-ligand complexes were determined at 25°C, according to a previously described method (38). Here, the change in absorbance, ⌬A p-v (with p and v representing the corresponding absorption maximum (peak) and minimum (valley) in the difference spectrum), was plotted versus the ligand concentration.…”