Acidic lens-protein-degrading activity in aqueous humour

Lens-protein-degrading activity in human aqueous humor was determined biochemically. Proteolytic activity was found in the pellet of aqueous humor from patients with Morgagnian cataract, traumatic cataract, after cataract, traumatic lens luxation, and phacolytic glaucoma. The activity was found at pH 3.8 and it was inhibited partly by pepstatin or leupeptin. Possibly, cathepsin D and lysosomal thiol proteinases in the macrophages play a major role in the degradation of escaping lens protein under pathologic conditions.