In this work, the binding of 2-hydroxy-3-nitro-9-fluorenone (HNF; a new reagent with antitumour activity) to human serum albumin (HSA) was investigated by fluorescence spectroscopy combined with UV-Vis absorption, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectrophotometric techniques under simulative physiological conditions for the first time. A strong fluorescence quenching reaction of HNF to HSA was observed and the quenching mechanism was suggested as static quenching according to the Stern–Volmer (S–V) equation. The binding constants of HNF with HSA at 300, 310 and 320 K were calculated as 6.08×10 5 , 3.80×10 5 and 2.79×10 5  M −1 , respectively, and corresponding numbers of binding sites ( n ) were 1.1, 1.0 and 1.0. Experimental results observed showed that the binding of HNF to HSA induced conformational change of HSA. The quantitative analysis data of CD spectra from that of the α-helix 60.3% in free HSA to 56.5% in the HNF–HSA complex further confirmed that the secondary structure of the protein was modified by HNF. The thermodynamic parameters, standard enthalpy change (Δ H °) and the standard entropy change (Δ S °), were obtained to be −31.10 kJ mol −1 and 6.87 J mol −1  K −1 , respectively, which indicated that a hydrophobic force played a major role in the interaction of HNF with HSA. All these experimental results and theoretical data clarified that HNF could bind to HSA and be effectively transported and eliminated in body, which could be a useful guideline for further drug design.

The study on the interaction between human serum albumin and a new reagent with antitumour activity by spectrophotometric methods

Antibodies are essential components of an adaptive immune response. Immunoglobulin G (IgG) is the most common type of antibody found in circulation and extracellular fluids. Although IgG alone can directly protect the body from infection through the activities of its antigen binding region, the majority of IgG immune functions are mediated via proteins and receptors expressed by specialized cell subsets that bind to the fragment crystallizable (Fc) region of IgG. Fc gamma (γ) receptors (FcγR) belong to a broad family of proteins that presently include classical membrane-bound surface receptors as well as atypical intracellular receptors and cytoplasmic glycoproteins. Among the atypical FcγRs, the neonatal Fc receptor (FcRn) has increasingly gained notoriety given its intimate influence on IgG biology and its ability to also bind to albumin. FcRn functions as a recycling or transcytosis receptor that is responsible for maintaining IgG and albumin in the circulation, and bidirectionally transporting these two ligands across polarized cellular barriers. More recently, it has been appreciated that FcRn acts as an immune receptor by interacting with and facilitating antigen presentation of peptides derived from IgG immune complexes (IC). Here we review FcRn biology and focus on newer advances including how emerging FcRn-targeted therapies may affect the immune responses to IgG and IgG IC.

/pdf/the-neonatal-fc-receptor-fcrn-a-misnomer-3mlk4qes2z.pdf

The Neonatal Fc Receptor (FcRn): A Misnomer?

Present review article highlights various cardiovascular risk prediction biomarkers by incorporating both traditional risk factors to be used as diagnostic markers and recent technologically generated diagnostic and therapeutic markers. This paper explains traditional biomarkers such as lipid profile, glucose, and hormone level and physiological biomarkers based on measurement of levels of important biomolecules such as serum ferritin, triglyceride to HDLp (high density lipoproteins) ratio, lipophorin-cholesterol ratio, lipid-lipophorin ratio, LDL cholesterol level, HDLp and apolipoprotein levels, lipophorins and LTPs ratio, sphingolipids, Omega-3 Index, and ST2 level. In addition, immunohistochemical, oxidative stress, inflammatory, anatomical, imaging, genetic, and therapeutic biomarkers have been explained in detail with their investigational specifications. Many of these biomarkers, alone or in combination, can play important role in prediction of risks, its types, and status of morbidity. As emerging risks are found to be affiliated with minor and microlevel factors and its diagnosis at an earlier stage could find CVD, hence, there is an urgent need of new more authentic, appropriate, and reliable diagnostic and therapeutic markers to confirm disease well in time to start the clinical aid to the patients. Present review aims to discuss new emerging biomarkers that could facilitate more authentic and fast diagnosis of CVDs, HF (heart failures), and various lipid abnormalities and disorders in the future.

/pdf/emerging-risk-biomarkers-in-cardiovascular-diseases-and-4h6ny67frw.pdf

Emerging Risk Biomarkers in Cardiovascular Diseases and Disorders

Ability of reconstituted high density lipoproteins to inhibit cytokine-induced expression of vascular cell adhesion molecule-1 in human umbilical vein endothelial cells

Publisher Summary This chapter summarizes the various studies of the movement of Ig subunits—that is, segmental flexibility as well as internal motion in the subunits themselves, and discusses the functional implications of these motions Immunoglobulins (Igs) are among the most thoroughly studied multifunctional protein molecules They unite the recognition function—namely, the ability to form complexes with a vast array of antigen molecules-—with effector functions, such as complement activation and the capacity to react with different cell receptors The functional sites responsible for all of these reactions are located in various domains, linked together with greater or lesser flexible segments of peptide chains The chapter provides strong evidence for the presence of diverse kinds of internal motion in the Ig molecule, which have evolved in favor of optimal interactions with various ligands There is little doubt that the Fab arms of Ig molecules have enough freedom to rotate relatively independently This so-called hinge flexibility, which is primarily dependent, in IgG, on the structure of the part of the hinge region between the hinge core and the Fab portion, greatly facilitates bivalent recognition of variably spaced antigenic determinants and permits the binding of two antigenic molecules or cells The functional sites are located in different parts of the Ig molecule, and flexibility seems to be a crucial factor for optimal binding to several different ligands

Internal movements in immunoglobulin molecules.

Spin-label study of segmental flexibility of anti-hapten antibodies. Precipitating pig anti-Dnp antibody is more flexible than non-precipitating.

Conformational changes of aspartate aminotransferases in the region of Cys-45 residue observed by means of spin label

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2874%2980971-3

Application of spin-labeled vitamin B6 analogues for the study of aspartate aminotransferase.

Binding of partially reassembled high-density lipoprotein to isolated human small intestine epithelial cells. Effect of lipid composition

1.

A new method was proposed for the synthesis of triacetoneamine (2,2, 6, 6-tetramethyl-4-piperidone).




2.

Five spin-labeled vitamin B6 derivatives were synthesized.

A. Yu. Misharin

Papers

Spin-label study of segmental flexibility of anti-hapten antibodies. Precipitating pig anti-Dnp antibody is more flexible than non-precipitating.

Conformational changes of aspartate aminotransferases in the region of Cys-45 residue observed by means of spin label

Application of spin-labeled vitamin B6 analogues for the study of aspartate aminotransferase.

Binding of partially reassembled high-density lipoprotein to isolated human small intestine epithelial cells. Effect of lipid composition

Spin-labeled derivatives of vitamin B6