2007-03-18 11:40:33 · 2 answers · asked by Bhaumik P 2 in Science & Mathematics ➔ Biology
The Mechanism of Guanosine Nucleotide Hydrolysis by p21 c-Ha-ras 3
2007-03-18 12:52:50 · answer #1 · answered by OK 3 · 0⤊ 1⤋
GTP stands for Guanosine TriPhosphate. The three phosphate groups are attached to the 5' carbon of ribose. They are named alpha, beta and gamma starting from the 5' carbon. The y is the lowercase Greek letter gamma and S is the symbol for sulfur. That means the last phosphate group, farthest from the ribose has been replaced with a thiol (sulfur) group.
GTPyS is used to inhibit reactions that hydrolyze (breakdown) GTP. The electron orbitals of the thiol group are different from phosphate so the enzymes that usually hydrolyze GTP are unable work. GTPyS will sit in the active site of GTPases and prevent the enzyme from working.
2007-03-19 18:29:59 · answer #2 · answered by Slackenerny 4 · 1⤊ 0⤋