The effects of abnormal folding patterns of alkaline phosphatase on enzyme
Benet Tribble, BSCI105, Section 5222, Spring 2008
Alkaline phosphatase, an enzyme which is produced in the liver, bile ducts, and
bones, may be involved in a rare form of osteoporosis that causes bone density loss and
liver disease (Lanford 2008). It is believed that the cause of this form of osteoporosis is
due to the denaturation of the enzyme. If the enzyme were to fold abnormally, then its’
function may be affected. The effect of the enzyme can be measured through its’
effectiveness of removing a phosphate group from the chemical p-nitrophenyl phosphate,
and can be tested under conditions that would denature the enzyme, determining whether
or not denaturing the enzyme affects its’ function. It was determined that abnormal
folding of the enzyme shifts the pH range for which the enzyme operates most efficiently.
Understanding the conditions that enzymes work efficiently will aid in the research of
Enzymes increase the rate of biological reactions that if some were otherwise not
accelerated it would deem life unsustainable for organisms (Weissman, 2007). Enzymes
have characteristic folded amino-acid chains that gives the enzymes its’ three
dimensional shape (Wellner, 2007). Denaturation is when enzyme activity level drops
due to amino acid chain unfolding. This unfolding occurs at high temperatures, high pH,
alkaline conditions, or when there is a change in the medium’s polarity (Wellner, 2007).
Alkaline phosphatase (AP) is produced mainly in the liver, bile ducts, and bone,
and it appears that AP facilitates the formation and ossification of bone (Lanford, 2008).
AP, which operates best in pH 10 mediums, could potentially alter the formation and
ossification of bone if denaturation occurs within the enzyme (Schmedlap, 1998). It is
hypothesized that low AP activity is due to an abnormal folding of the amino acid chains
of the enzyme from denaturation. Many tests can be employed to test this hypothesis, as
factors of enzyme function such as varying pH levels and temperatures can be controlled
in a lab situation. When AP and
nitrophenyl phosphate (PNP) are incubated together,
AP removes the phosphate group, resulting in a yellow molecule known as
nitrophenol. Concentrations of the formation of this product (which is indicative of the
activity level of AP) can be measured by way of spectrophotometer due to the yellow
-nitrophenol (Lanford, 2008).
Materials and Methods