Team:Korea U Seoul/Project/sub result

The overall reaction for precipitation is

Ca2++HCO3-→ CaCO3+H+

According to that equation, CaCO3 generated the more the pH will be lowered.
NA, R and CA is cloning different proteins. NA is expressed from full gene of nacrein, R from nacrein's repeated domain and CA from carbonic anhydrase. The effect of NA and R on the rate of precipitation of CaCO3 was determined by recording the decrease in pH of a 20mM Tris HCl pH8.0 buffer solution at 10°C



In this graph shows drop of pH and according to above, drop of pH means CaCO3 is madden. By the result we can knew that there is no differ between 3 samples. Our hypothesis was repeat domain binding with Ca so precipitation will decrease.


However in our data there's no gap between 3 sample. So we make another hypothesis that R or NA is precipitate with CaCO3. Our team start to check that and it will be our further study.



we also check CA activity to check NA and CA can role in carbonic anhydric reaction

By the result we can see that CA activity of NA is biger than formal condition(Tris) but CA is lower. It means NA act as a catalyst but CA act as a inhibitor. It can be explain by le chatelier's principle. Because of transition of carbonic acid caused by CA, reaction equilibrium in carbonic acid fixation by calcium ion is shift from forward to inverse. That's why CaCO3 decrease when CA is treated. But in the case of NA, R domain capture CO3 immediately so carbonic acid is decrease. So reaction equilibrium shift to forward and can be active continue.