Search

A conductometric enzyme biosensor using proteinase K was developed and then tested to relate its electrical signal to the number of proteinase K hydrolysis sites in bovine serum albumin (BSA) and angiotensin, a ten amino acid peptide, with one cleaving site.The conductometric sensor presents a large linear range of response for BSA and angiotensin ranging from 0.5 to 8 mg/l and from 4 to 8 mg/l, respectively. For a same tested concentration (mg/l), the response for native BSA is 12 times higher than for angiotensin. Aspartam was used as negative test and no response was obtained with the proteinase K biosensor. The conductometric sensor permitted also to detect difference on enzyme activity on native and non-native BSA, a response three times higher was obtained for non-native BSA. Keywords: Conductometric biosensor, Proteinase K, Bovine serum albumin, Angiotensin, Aspartam

Lanthanum-manganese based perovskites were prepared, both at atmospheric pressure (MW) and at higher pressure (MWHyd), under microwaves irradiation. Structural and physico-chemical properties of the catalysts were investigated using X ray diffraction, X-ray photoelectron spectroscopy (XPS), BET-sorption, and temperature programmed reduction-, or desorption coupled with mass spectrometry, (TPR-MS or TPD-MS). While MW and MWHyd catalysts exhibited the same XRD patterns indexed as pure perovskite structure, their surface physico-chemical properties were found to be strongly influenced by the preparation procedure. The influence of the nature of oxygen species, their amount and their mobility, evidenced by temperature programmed experiments, on the catalytic properties in catalytic combustion of methane in the presence and in the absence H 2 S has been studied.