OBJECTIVE: Oxidative stress is implicated in the pathophysiology of diabetes mellitus and its chronic complications. The aim of this study was to evaluate plasma antioxidant status in patients with...

https://journals.sagepub.com/doi/pdf/10.1177/147323001204000235

Increase in total antioxidant capacity of plasma despite high levels of oxidative stress in uncomplicated type 2 diabetes mellitus.

Ceruloplasmin (CP), the multicopper oxidase of plasma, interacts with myeloperoxidase (MPO), an enzyme of leukocytes, and inhibits its peroxidase and chlorinating activity. Studies on the enzymatic properties shows that CP behaves as a competitive inhibitor impeding the binding of aromatic substrates to the active centre of MPO. The contact between CP and MPO probably entails conformational changes close to the p-phenylenediamine binding site in CP, which explains the observed activation by MPO of the substrate's oxidation. CP subjected to partial proteolysis was virtually unable to inhibit activity of MPO. The possible protein-protein interface is comprised of the area near active site of MPO and the loop linking domains 5 and 6 in CP. One of the outcomes of this study is the finding of a new link between antioxidant properties of CP and its susceptibility to proteolysis.

Ceruloplasmin and myeloperoxidase in complex affect the enzymatic properties of each other.

In the last 20 years, several new genes and proteins involved in iron metabolism in eukaryotes, particularly related to pathological states both in animal models and in humans have been identified, and we are now starting to unveil at the molecular level the mechanisms of iron absorption, the regulation of iron transport and the homeostatic balancing processes. In this review, we will briefly outline the general scheme of iron metabolism in humans and then focus our attention on the cellular iron export system formed by the permease ferroportin and the ferroxidase ceruloplasmin. We will finally summarize data on the role of the iron binding protein lactoferrin on the regulation of the ferroportin/ceruloplasmin couple and of other proteins involved in iron homeostasis in inflamed human macrophages.

The ferroportin-ceruloplasmin system and the mammalian iron homeostasis machine: regulatory pathways and the role of lactoferrin.

Expression of the carbohydrate recognition domain of FimH and development of a competitive binding assay.

An enzyme-linked immunosorbent assay (ELISA) for rat α2-macroglobulin (α2M) using a monoclonal antibody was developed, and used to measure α2M in sera from rats injected intramuscularly with turpentine oil as an inflammatory agent. The mean concentration of α2M gradually increased and peaked 2 days after the turpentine oil injection. The peak α2M concentration ranged from 2362–8472 µg/ml (mean 4531 µg/ml), which was 50–290 times higher than the pre-dosing levels of 23–61 µg/ml. In addition, interleukins (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, and interferon (IFN)-γ were measured using commercial ELISA reagent kits. IL-6 and IL-8 increased and peaked 12 h after turpentine oil injection, the levels being 5–51 times and 2–38 times the pre-dosing ones, respectively. The concentrations of IL-1, IL-2, IL-4, IL-10 and IFN-γ in rats injected with turpentine oil did not change.

https://lan.sagepub.com/content/36/2/153.full.pdf

Serum α2-macroglobulin and cytokine measurements in an acute inflammation model in rats

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793%2898%2901253-8

Requirement of intact human ceruloplasmin for the glutathione-linked peroxidase activity

Coating efficiency of rat and human serum a 1 -acid glycoprotein (a 1 -AGP) was investigated for competitive enzyme immunosorbent assays with antigen immobilized on the solid phase by using different pHs and buffers. Blocking materials and pH of coating buffer had a marked influence on the amount of a 1 -AGP that binds to plate. Usually, carbonate buffer is used at pH 9.6 or 9.0, but phosphate buffered saline (PBS) at pH 7.2 can be used for an effective coating. At pH 7.2, coating of a 1 -AGP in Tris buffered saline was five - tenfold as effective as in PBS and phosphate buffer. Blocking of uncoated surface with casein was ten - twenty times as effective as with fetal bovine serum albumin for coating of a 1 -AGP.

Coating efficiency of a 1 -acid glycoprotein in competitive enzyme immunosorbent assays with antigen immobilized on the solid phase

A competitive enzyme linked immunosorbent assay with antigen immobilized on the solid phase was developed to measure alpha 2-macroglobulin in rat serum. The cross reactivity with albumin and hemoglobin was eliminated by use of IgG fractions that were isolated after chromatography on Cibacron Blue F3-GA Sepharose immobilized rat whole serum and hemoglobin Sepharose. Blocking materials and pH of the coating buffer had no effect on the amount of alpha 2-macroglobulin that binds to the plate. When the coating amount of alpha 2-macroglobulin was 100 ng/well, at pH 7.4, 10 mM Tris-HCl containing 150 mM sodium chloride and the IgG amount added was 60 ng/well, then albumin and hemoglobin did not affect the assay at concentrations of 150 micrograms/ml or 200 micrograms/ml. This assay is useful for measuring the concentration of alpha 2-macroglobulin in normal and irradiated rat serum.

https://iubmb.onlinelibrary.wiley.com/doi/pdf/10.1080/15216549700204501

In Gyu Kim

Papers

Requirement of intact human ceruloplasmin for the glutathione-linked peroxidase activity

Coating efficiency of a 1 -acid glycoprotein in competitive enzyme immunosorbent assays with antigen immobilized on the solid phase

Development of a competitive enzyme linked immuno sorbent assay to measure α2-macroglobulin in irradiated rat serum