34 吃了一餐富含糖分的食物，經過消化吸收，血中葡萄糖上升、「insulin/glucagon」上升，insulin 與 insulin receptor 結合引起細胞內 signal transduction。下列關於 insulin receptor的敘述何者錯誤?
(A)insulin receptor is a receptor enzyme
(B)binding of insulin to the receptor activates a protein kinase
(C)the insulin receptor then phosphorylate a transcription factor directly
(D)The insulin receptor is a tyrosine kinase