Abstract

In humans, an inherited mutation in the alkaline phosphatase gene is responsible for defective bone mineralization¹.  Studies show that reduced activity of alkaline phosphatase (AP) results in such a defect¹. Previous experiments in Streptomyces griseus have shown that when AP coded by the phoA gene is exposed to Zn²⁺ ions, AP activity is significantly inhibited². Therefore, we hypothesize mutations to the zinc-binding region of AP coded by the strK gene will increase AP activity since less Zn²⁺ ions will bind to cause inhibition. Our preliminary experiments determine the V-max and optimum pH level for AP using pancreas tissue of Homarus americanus. To better understand mutations to the conserved zinc-binding site of AP, oligonucleotide primers were designed to amplify this region using Polymerase Chain Reaction. Follow-up research could mutate the isolated zinc-binding region to observe effects on AP activity.  Furthermore, finding ways to increase AP activity in humans can lead to proper bone mineralization.

References

1. Henthorn et al. (1992). Different missense mutations at the tissue non-specific Alkaline Phosphatase gene locus in autosomal recessively inherited forms of mild and severe hypophosphatasia. Proceedings of the National Academy of Sciences.

2. Moura et al. (2001). Substrate analysis and molecular cloning of extracellular alkaline phosphatase of Streptomyces griseus. Microbiology.

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These authors made this poster for Biology 221: Cell and Molecular Biology taught by Dr. Karen Kirk.