Which statement concerning receptor enzymes is CORRECT? They are not usually membrane-associated proteins. They contain an enzyme activity that acts on a cytosolic substrate. They contain an enzyme activity that acts on the extracellular ligand. They have an active site on the extracellular side of the membrane.

Explanation:

Receptor enzyme have three domains, i) extracellular domain, ii) trans-membrane domain and iii) cytosolic  domain.

They contain an enzyme activity that acts on a cytosolic substrate side.

They contain one of the following function:

Tyrosine kinase activity, tyrosine phosphatase activity, serine or threonine kinase activity, and guanylyl cyclase activity.