Question

Match the following: 1. G-protein 2. Phospholipase kinase (PLC) 3. Diacylgylceral (DAG) 4. Calmodulin 5. Calcium a. Binds to calcium and activates other proteins b. Stored in the smooth ER and binds to proteins to change their conformation c. Splits PIP2 into IP3 and DAG d. Activity is regulated by GTP and GDP e. Activates protein kinase C and is a part of PIP2

Answer 1

1. G protein - activity is regulated by GTP and GDP

Explanation: G protein belongs to the class of GTPase enzyme in which the activity of the enzyme is regulated by the binding of GTP and GDP. When it is bound to GTP it will be activated and will be in inactivated state when bound to GDP.

2. Phospholipase kinase (PLC) - splits PIP3 to IP3 and DAG.

Explanation: The role of PLC is to split PIP3 into two molecules, IP3 and GAG which are involved in the signal transduction pathway.

3. Diacylgylceral (DAG) - Activates protein kinase C and is part of PIP2.

Explanation: The hydrolysis of PIP2 produces DAG and it activates the protein kinase C.

4. Calmodulin - Binds to calcium and activates other proteins
Explanation: Calmodulin is a calcium modulated protein which detects the calcium levels and sends signal to calcium sensitive enzymes. Calmodulin binding with calcium ions allows the protein to interact with different other proteins.

5. Calcium - Stored in smooth ER and binds to proteins to change their conformation.

Explanation: The calcium are stored in the smooth endoplasmic reticulum and the binding of calcium to the proteins induces change in their conformation.