This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Which of the  following enzyme is not regulated by calcium or calmodulin? \nSelect and explain. \nA. Adenylate cyclase, B. Glycogen synthase, C. Guanylyl cyclase, D. Hexokinase', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Calmodulin\xa0 mediated\xa0 action\xa0 of\xa0 Ca2+ :\xa0Calmodulin (mol.\xa0 wt.\xa0 17,000) is\xa0 a\xa0 calcium\xa0binding\xa0 regulatory\xa0 protein.\xa0 Ca-calmodulin\xa0complex\xa0 activates\xa0 certain\xa0 enzymes\xa0\ne.g.\xa0adenylate cyclase,\xa0 Ca2+\xa0 dependent\xa0 protein\xa0kinases.\nRef: Satyanrayana, Ed 3, page no 405', 'role': 'assistant'}]