Biological activity of hemoprotein nitrosyl complexes

Chemical and biological functions of hemoprotein nitrosyl complexes as well as their photolysis products are discussed in this review. Chemical properties of nitric oxide are discussed, and major chemical reactions such as interaction with thiols, free radicals, and transition metals are considered. Specific attention is paid to the generation of hemoprotein nitrosyl complexes. The mechanisms of nitric oxide reactions with hemoglobin and cytochrome c and physicochemical properties of their nitrosyl complexes are discussed. A review of photochemical reactions of nitrosyl complexes with various ligands is given. Finally, we observe physiological effects of visible radiation on hemoprotein nitrosyl complexes: smooth muscle relaxation and reactivation of mitochondrial respiration.     

Biological activity of ruthenium nitrosyl complexes

Nitric oxide plays an important role in various biological processes, such as neurotransmission, blood pressure control, immunological responses, and antioxidant action. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO-carriers. Coordination compounds, in particular ruthenium(III) and (II) amines, are good NO-captors and -deliverers. The chemical and photochemical properties of several ruthenium amine complexes as NO-carriers in vitro and in vivo have been reviewed. These nitrosyl complexes can stimulate mice hippocampus slices, promote the lowering of blood pressure in several in vitro and in vivo models, and control Trypanosoma cruzi and Leishmania major infections, and they are also effective against tumor cells in different models of cancer. These complexes can be activated chemically or photochemically, and the observed biological effects can be attributed to the presence of NO in the compound. Their efficiencies are explained on the basis of the [Ru^IINO⁺]³⁺/[Ru^IINO⁰]²⁺ reduction potential, the specific rate constant for NO liberation from the [RuNO]²⁺ moiety, and the quantum yield of NO release.     

Hydrodynamic properties of macromolecular complexes. I. Translation

We have developed an improved theory for calculating the translational frictional coefficients of rigid macromolecular complexes composed of unequal spherical subunits. The Yamakawa hydrodynamic interaction tensor, which improves on the Oseen tensor by taking account of the finite sizes of the frictional subunits, has been generalized to accomodate nonidentical subunits. Iterative numerical methods are described for solving the set of simultaneous hydrodynamic interaction equations, thus avoiding preaveraging. The theory is applied to prolate ellipsoids of revolution, to lollipops, and to dumbbells, and comparison is made with earlier, more approximate theories.     

Biological activity of sulphur ylides. I. Antimicrobial properties of some new carbonyl stabilized sulphonium ylides

Antimicrobial properties of some new carbonyl stabilized sulphonium ylides have been tested against two bacteria Staphylococcus aureus, Escherichia coli and two fungi Alternaria alternata and Curvularia lunata. The potent antifungal activity of these compounds suggest their practical applications in fungicidal formulations and other pharmacological preparations.     

Comparative characteristics of soluble and membrane brain aminopeptidases. I. Isolation, physico-chemical properties, catalytic activity

The methods were worked out for isolating of the bovine brain soluble and membrane-bound aminopeptidases in highly purified state. One of the stages involved a biospecific-type chromatography on aminohexyl-Sepharose. Both enzymes were found to have equal molecular masses (ca. 100-107 kD) and isoelectric points (pI 4,6). None of the enzymes possessed a subunit structure. Both aminopeptidases were inactivated by omicron-phenanthroline and by an SH-reagent, p-hydroxymercuribenzoate. The catalytic constants for the hydrolysis of a specific substrate, L-leucine p-nitroanilide, were identical for the two enzymes. So far no differences in the physico-chemical or enzymatic properties of the soluble and membrane-bound enzymes were disclosed.     

Conformation properties and enzymatic activity of pancreatic ribonuclease in soluble complexes with sodium dextran sulfate

Effect of complex formation with dextran sulfate (DS) (substitution degree 1.3, molecular mass 500 thousand) on RNAse enzymic activity. its spatial structure and conformation stability was studied. Hydrolytic activity of the enzyme in complex in inhibited already at small additions of DS, while the transferase one is changed only at a great excess of the polyelectrolyte. It has been shown by CD spectra that no notable conformation changes proceed in the enzyme during complex formation, although the enzyme turns destabilized to the denaturing effect of heat at the expense of strengthened interactions between DS and RNAse during its denaturation. Thus the inhibition of hydrolytic activity in the complex is primarily related to limitations for the formation of the enzyme-substrate complex on polyelectrolyte charged likely with the substrate, and not to the protein conformation changes.     

An unexpected effect of an ouabain-sensitive ATPase activity on the amount of antigen-antibody complexes formed in situ.

A classical method of indirect immunofluorescence was applied on various kinds of lightly fixed and permeabilized cells to analyze the formation of the complexes between a nuclear antigen and its antibody (AAC). The amount of AAC decreased dramatically when the incubation with the first antibody was realized in the presence of ATP in a sodium-rich medium with 0.5 mM KCl. Addition of sodium vanadate, a general inhibitor of ATPases, ouabain or tetrabutylammonium ion, specific inhibitors of the Na+,K+-ATPase, prevented this effect. The established role of this enzyme is to increase free-K+ concentration and decrease free Na+ concentration in the cell. It is not surprising to find an ATPase still active since light fixation and permeabilization do not destroy phosphatases. But it is rather surprising to find something looking like Na+,K+-ATPase activity in permeabilized cells. The importance of potassium in this puzzling result is suggested by the fact that appearance of ACC was equally suppressed if the incubation was made in the absence of ATP in a potassium-rich medium without sodium. Results are discussed, taking into account the properties of cell-associated water and recently found interrelation between Na+,K+-ATPase and tubulin. In any case, the results seem interesting in the field of immunocytochemistry.     

Biological complexes of poly-beta-hydroxybutyrate.

Short-chain complexed poly-beta-hydroxybutyrate, 130-170 monomer units, is a ubiquitous constituent of cells, wherein it is usually associated with other macromolecules by multiple coordinate bonds, or by hydrogen bonding and hydrophobic interactions. This conserved PHB has been isolated from the plasma membranes of bacteria, from a variety of plant tissues, and from the plasma membranes, mitochondria, and microsomes of animal cells. In bacterial membranes, PHB has been found complexed to the calcium salts of inorganic polyphosphates, and to single-stranded DNAs. The ability of PHB to solvate salts, consisting of cations having high solvation energies and large delocalized anions, is in accordance with its molecular characteristics, that of a flexible linear molecule possessing a large number of electron-donating ester oxygens suitably spaced to replace the hydration shell of cations. In turn, PHB may be rendered soluble in aqueous media by complexation to water-soluble proteins, such as serum lipoproteins and albumin. Such solvates are highly resistant to hydrolytic enzymes. These findings suggest that the physiological roles of this unique biopolymer may include the solvation of salts of polymeric anions to facilitate their movement through hydrophobic barriers, and the protection of cellular polymers from enzymatic degradation.     

Precipitation of radiolabeled antigen-antibody complexes with protein A-containing Staphylococcus aureus.

The feasibility of using protein A-containing Staphylococcus aureus to measure antibodies in sera from several mammalian species was studied. A variety of unrelated radiolabeled antigens were tested, including components of bovine serum, DNA, and bacterial and tumor-associated extracts. The use of S. aureus was found to be a reliable way to detect and measure the primary interactions between many of the antigens and antibodies tested. Results were equivalent under many circumstances to those obtained with the ammonium sulfate and heterologous anti-immunoglobulin methoods. However, some of the limitations noted were that certain antigens bound directly to S. aureus and that all classes of human immunoglobulins tested, in particular IgG3 and IgA1, were not precipitated by S. aureus. If these limitations are taken into consideration, the use of S. aureus can be of value in studying immunochemical reactions with other antigens.     

Biological activity of synthetic subunits of streptococcus peptidoglycan. I. Pyrogenic and thrombocytolytic activity.

The ability of some synthetically prepared analogues of Streptococcus peptidoglycan subunits (dipeptide, tetrapeptide, glycodipeptide and glycotetrapeptide) to cause fever in rabbits and lysis of rabbit blood platelets was studied. While di- and tetrapeptides did not exhibit these activities, glycodipeptides and glycotetrapeptides displayed pyrogenic and thrombocytolytic activities comparable with those of natural peptidoglycans.