"The potential rates of exoenzymatic activities (leucineaminopeptidase, LAP; beta-glucosidase, b-GLU; alkaline phosphatase, AP) involved in the degradation of proteins, polysaccharides and organic phosphates, respectively, were measured according to Hoppeâ²s method using the fluorogenic compounds L-leucine- 4-methylcoumarinyl-7-amide, 4-methylumbelliferyl-b-Dglucopyranoside and 4-methylumbelliferyl phosphate (Sigma-Aldrich, Co) as substrates for LAP, b-GLU and AP, respectively. Substrates were added at increasing concentrations (ranging from 0.2 to 4 mM final concentrations) to triplicate sub-samples and blanks, incubated, in the dark, for 2-3 hours at âin situâ Â±1Â°C temperature The increase in fluorescence intensity, measured by a spectrofluorometer, was converted into the amount of substrate potentially hydrolysed. The maximum velocity of hydrolysis (Vmax) was calculated for each sample after linear (Lineweaver- Burk) transformation of the Michaelis- Menten equation. The Michaelis-Menten constant (Km= 1/2 Vmax) as an index of the affinity or strength of binding between the enzyme and its substrate, was also calculated using the same linear transformation.
Gabriella Caruso; Patterns of Prokaryotic Activities and Abundance among the Epi-Meso and Bathypelagic Zones of the Southern-Central Tyrrhenian Sea"A journal is a periodical publication intended to further progress of science, usually by reporting new research. Most journals are highly specialized, although some of the oldest journals publish articles, reviews, editorials, short communications, letters, and scientific papers across a wide range of scientific fields. Journals contain articles that peer reviewed, in an attempt to ensure that articles meet the journal's standards of quality, and scientific validity. Each such journal article becomes part of the permanent scientific record.
Last date updated on November, 2020