The effect of alanine substitutions for known or potential GC-B phosphorylation sites on guanylyl cyclase activity and indication of conservation of sites in GC-A and sea urchin guanylyl cyclases is shown.

*Indicates alanine substitution reduced guanylyl cyclase activity but receptor was determined to be incompletely glycosylated and phosphorylated.* 本标注表示：丙氨酸替换（alanine substitution）可降低鸟苷酸环化酶（guanylyl cyclase）活性，但该受体经鉴定存在糖基化不完全且发生磷酸化修饰的情况。