Why is mgatp2− , instead of atp4− , a substrate for the hexokinase reaction? select two correct phrases. mg2+ prevents atp hydrolysis. hexokinase cannot bind atp when it is not complexed with mg2+ . mg2+ makes the (terminal) phosphorus atom of atp more accessible to electrophilic attack by a glucose –oh group. mg2+ shields the negative charges of two of the phosphate oxygen atoms of atp. mg2+ makes the (terminal) phosphorus atom of atp more accessible to nucleophilic attack by a glucose –oh group.

Mg is able to give off two of its electrons to other molecule, not four. ATP, in this case is the aceptor of those electrons

Two correct answers are:

1) Hexokinase cannot bind active ATP when it is not complexed with Mg2+

2) Mg2+ makes the terminal phosphorus atom of ATP more accessible to nucleophilic attack by a glucose-OH group

Explanation:

As Mg occurs naturally as ion Mg++, it is able to give off only two of its electrons to other molecule, then it is possible for ATP to receive two electrons of Mg, forming MgATP2-

The hexokinase reaction, here cited, corresponds to the glucose phosphorylation of its sixth carbon to produce glucose-6-P, which is a glycolysis intermediate. In this way glucose is activated (ATP is initially invested to energize glucose).  Later on, Glyceraldehide-3-P is produced, and finally converted to pyruvate, NADH2 and ATP