Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in vitro metabolic degradation of human interleukin (IL)-1beta was studied using lysates of rat kidney lysosomes, and proteases involved in the degradation were identified. In the study of IL-1beta degradation, fluorescein isothiocyanate (FITC)-labeled IL-1beta was used as a substrate. The maximal degradation of IL-1beta occurred at pH 3.0, and the reaction was proportional to the lysosomal protein concentration and time of incubation. The degradation was stimulated by the addition of L-cysteine. The reaction was not inhibited by phenylmethanesulfonyl fluoride or EDTA, indicating that serine proteases or metalloproteases do not play a major role in the degradation process. N-Ethylmaleimide, leupeptin and E-64, inhibitors of thiol protease, inhibited the degradation of IL-1beta, by 59%-70%. Pepstatin A, an inhibitor of carboxyl protease, inhibited the degradation by 58%. Combinations of thiol and carboxyl protease inhibitors nearly completely inhibited the degradation. Bio-Gel P-10 gel filtration chromatography of in vitro reactants confirmed the ability of lysosomal proteases to degrade IL-1beta and revealed four to five peaks of degradation products. Taken together, these results indicate that thiol protease and carboxyl protease play an important role in the IL-1beta degradation process by kidney lysosomes. Leupeptin and E-64 dose dependently inhibited both cathepsin B and cathepsin L activities, and pepstatin A strongly inhibited cathepsin D activity in rat kidney lysosomes. The present results suggest that cathepsin B, cathepsin L, and cathepsin D in kidney lysosomes are involved in the metabolic degradation of human IL-1beta.
J Interferon Cytokine Res 1999 Apr
PMID:Proteases involved in the metabolic degradation of human interleukin-1beta by rat kidney lysosomes. 1033 87

Interleukin-2 (IL-2) is a 15 kDa cytokine secreted by T-cells. Consequence to its natural function as locally secreted short-term messenger, its half-life in circulation is short and provided mainly by fast renal clearance due to its low molecular weight and its proteolytic susceptibility. These are common characteristics for most cytokines, resulting in low clinical utility. In this study we report the construction of an IL-2 fusion-protein comprising a protective anti-hIL-2 single chain antibody that was selected from a phage display library and the hIL-2. This IL-2 fusion-protein is fully human and resistant to inactivation by the ubiquitous lysosomal protease-cathepsin D, which is implicated in the in vivo inactivation of IL-2. In contrast, the native IL-2 lost practically all of its activity under these conditions. This resistance is due to the interaction of the single chain domain with its epitope on IL-2 thus masking possible cleavage sites. We suggest that this 45 kDa proteolysis resistant IL-2 fusion-protein upon further increase of its molecular weight by common fusion techniques to at least 75 kDa will exhibit significantly longer half-life in vivo and a higher clinical utility than either the native IL-2 or any of its reported long T/2 derivatives.
Cytokine 2003 Jun 07
PMID:Construction of proteolysis resistant human interleukin-2 by fusion to its protective single chain antibody. 1284 61