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Biomedical subjects

S F Russo

Publications and source records attributed to S F Russo.

9 recordsLinked to original sources
PubMed1983

A fluorescent probe for the active site of bovine trypsin.

The compound 2-p-toluidinylnaphthalene-6-(N-beta-ethylamine hydrochloride) sulfonamide (compound III) has a structure that is appropriate for binding to the active site of trypsin. It also has the property of fluorescence when in a nonpolar environment such as when bound to trypsin. Kinetic studies show that compound III competitively inhibits the trypsin-catalyzed hydrolysis of L-alpha-N-Benzoylarginine-p-nitroanilide (L-BAPNA) with a KI' of 3.6 X 10(-4)M at pH 8.1. The fluorescence enhancement of III when bound to bovine trypsin further confirms the existence of a hydrophobic specificity region within the active site of trypsin. The pH dependence of the fluorescence of compound III with trypsin was also determined.

Animals↗
PubMed1978

A fluorescent probe study of salmine AI.

A fluorescent probe, 1-p-toluidinylnapthalene-8-sulfonate (1,8-TNS), was used to study the nonpolar sites on salmine AI. Fluorescence enhancement resulting from binding between the probe and the protein occurs at a wavelength of maximum emission of 497-500 nm, indicating the existence of moderately nonpolar binding sites on salmine AI. Fluorescence enhancement decreases as the ionic strength of the solvent is increased from 0.002 M to 0.050 M. Fluorescence increases with increasing acidity although this effect is not correlated to the pKa of 1,8-TNS. Positive cooperative binding takes place between 1,8-TNS and salmine AI. Equilibrium dialysis indicates that binding occurs only under conditions resulting in significant fluorescent enhancement. The binding was also studied using thin film dialysis, which is much faster than equilibrium dialysis and avoids the observed changes in probe-protein interaction that occur over long time periods with the latter system.

Animals↗
PubMed1976

Fluorescent probe studies of haptoglobin type 2-1.

Haptoglobin is an alpha2 serum protein that forms an irreversible complex with hemoglobin. The combination between these two macromolecules resembles the binding of an antigen to its antibody except that the complex remains soluble. This investigation was undertaken to determine the nature of the hydrophobic sites on haptoglobin type 2-1. The interaction of 1-anilinonphthalene-8-sulfonate (ANS) with haptoglobin type 2-1 is characterized by a flourescence intensity in solutions containing ANS and haptoglobin as the pH is decreased from 9 to 4. The dissociation constant for the ANS interaction with haptoglobin 2-1 is 5.8 x 10--5 M at pH 7.0, 5.2 X 10--5 M at pH 5.0 AND 30.3 X 10--5 M at pH 4.0. Fmax shows no change in the pH range 6-9 but does show an increase at pH 4.0 when compared to the neutral region.

Anilino Naphthalenesulfonates↗