Biomedical subjects

K Bostancioglu

Publications and source records attributed to K Bostancioglu.

3 recordsLinked to original sources

PubMed1988

Conductimetry: a new tool for studying inhibition of elastolysis.

The conductimetric method was applied to the measurement of human leukocyte elastase activity, using insoluble elastin as a substrate. From conductance changes, initial rates of elastolysis were derived. A linear relationship of enzyme activity with enzyme concentration was demonstrated up to 400nM of enzyme, for three different substrates. In this concentration range, inhibition of elastolysis by eglin c was studied for different concentrations of eglin c. A 50% inhibitory concentrations of 0.13-0.15 microM of eglin c was derived from our results, corresponding to an inhibitor/enzyme ratio of about 0.5, indicating a strong inhibition, as previously demonstrated by authors using synthetic substrates.

Animals↗

PubMed1987

Elastolysis of normal and partially cross-linked elastin.

Rate of elastolysis by pancreatic and leukocyte elastases of normal and copper deficient porcine aortic elastins were measured using a conductimetric method. Kinetics obey to Michaelis-Menten model for both substrates and enzymes. KM and Vmax values derived from Lineweaver-Burk plots indicate that, if a near uniformity exists in KM, differences were observed in catalytic rates, kcat increasing approximately 40% for copper deficient elastin elastolysis by leukocyte elastase. This higher susceptibility to proteolysis may have implications for understanding turnover of elastin in tissues.

Animals↗

PubMed1986

Ca2+ and Mg2+ protection against thermal denaturation of pancreatic elastase.

Thermal denaturation of porcine pancreatic elastase was studied by difference spectrophotometry. At 293 nm, and pH 8.0, the thermal transition of elastase occurs with a midpoint temperature (Tm) of (58.0 +/- 0.5) degrees C. Mg2+ and Ca2+ stabilize the native form in increasing the midpoint temperature of the transition, Ca2+ being more effective than Mg2+ in the 0-0.02 M concentration range. Furthermore, Ca2+ protects pancreatic elastase against the destabilizing effect of Cu2+. Whatever be the temperature between 40 degrees C and 55 degrees C, Ca2+ protects pancreatic elastase against loss of enzymatic activity.

Animals↗