BACTcontrol microLAN - Page 57

microLAN b.v. BACTcontrol – User Manual – V0.4.4 Page 57 of 59
When the molar mass of an enzyme and the amount of converted substrate are
known, then the activity of the enzyme can be expressed as the molecular activity in
mol per time unit. One picomol equals 10
-12
mol.
Alkaline phosphatase is an enzyme that catalyzes the hydrolysis
1
of a chemical
structure. Like the name says, it is responsible for removing phosphate groups from
many types of molecules, including nucleotides, proteins, and alkaloids. This is called
dephosphorylating process. As the name suggests, alkaline phosphatases are most
effective in an alkaline environment. The optimal activity is at pH 8,0 at 25ºC / 77°F,
at pH 10 at 37°C / 98,6°F.
The purpose of the enzyme is not completely known. The hypothesis is that it is a
means for the bacteria to generate free phosphate groups for uptake and use. This is
supported by the fact that alkaline phosphatase is usually produced by the bacteria
only when the concentrations of phosphate in the environment are low.
For this reason this technique is useful as warning system on the production of drink
water, where the concentrations of phosphate are low. Beta-galactosidase is an
enzyme that catalyzes the hydrolysis of beta-galactosides into monosaccharide (short
molecules of sugar). In coliforms, the gene of β-galactosidase, is present as part of an
inducible system which is activated in the presence of lactose when glucose level is
low. This inducible system is activated by the addition of the reagent that corresponds
to coliform bacteria.
Beta-Glucuronidase is an enzyme that catalyzes the hydrolysis of complex
carbohydrates. Beta-Glucuronidase from E. coli is capable of very quickly hydrolyzing
of many compounds. β-Glucuronidase is used for the enzymatic hydrolysis of
glucuronides in biological fluids, primarily urine. This enzyme is activated by the
addition of the E.coli reagent.
The hydrolysis product (MU) fluoresce when it comes into contact with the proper
enzymes. The grade of activity of the enzyme catalyzing the hydrolysis is determined
by an increase in fluorescence per time. The fluorescence can be detected under long
wave UV light (366nm) as a blue or green fluorescence.
1
Hydrolysis, hydro, meaning water, and lysis, meaning separation usually means the cleavage of chemical bonds by
the addition of water.