protein nature in different pH? - (Feb/06/2008 )

hello all,

could some one correlate the pH and protein nature (hydrophobicity or hydrophilicity)?

example - a protein in acidic pH - will it become hydrophobic or hydrophilic? n a protein in basic pH?
or this behavior entirely depends on the protein and its pI?


thanks in advance.

---

depends on the protein and its pI.

at the pI the protein will have a net neutral charge and will be hydrophobic (this is an oversimplification but effective).

at a pH above the pI the protein will be negatively charged. below the pI the protein will be positively charged. both are hydrophilic (again, oversimplified).

actually, proteins are hydrophobic and hydrophilic at the same time (how much depends on amino acid content and sequence). you can push towards one or the other with the use of additives like ammonium sulfate, ethylene glycol, acetone, etc.

---

Yes, all you change with pH is the surface charge, which is quite different to the hydrophobicity.

---

thanks for u,

i just wanted to know the effect of pH on proteins, despite real hydrophobic or philic nature.

now it is clear. this clarifciation help me to perform effective ELISA for binding of proteins to plastic surfaces.

have a gud time.

---