Kallikrein and kininases in ocular tissues.

The retina, choroid, ciliary body, iris and aqueous humor of swine eyes contain enzymes capable of producing (kallikrein) and inactivating (kininase I and II) kinins. The activity of the enzymes varies in different eye structures. Higher activities of kallikrein and kininase II were found in highly vascularized tissues such as retina, choroid and ciliary body. The highest activity of kininase I (carboxypeptidase N) was found in the aqueous humor. The presence of these enzymes in the eye structures suggests a possible role for them in local metabolism of vasoactive peptides.