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Proteolytic conversion of xanthine dehydrogenase to xanthine oxidase: evidence against a role for calcium-activated protease (calpain).
Biochem Biophys Res Commun. 1989 Dec 15; 165(2):858-64.BB

Abstract

The present study tested the hypothesis that calpain is responsible for the limited proteolytic conversion of xanthine dehydrogenase (XD) to xanthine oxidase (XO). We compared the effects of various proteases on the activity and molecular weight of a purified preparation of xanthine dehydrogenase from rat liver. In agreement with previous reports, trypsin treatment produced a complete conversion of XD to XO accompanied by a limited proteolysis of XDH from an Mr of 140 kD to an Mr of 90 kD. Treatment with calpain I or calpain II did not produce a conversion from XD to XO nor did it result in partial proteolysis of the enzyme. Similarly, trypsin treatment partially degraded a reversibly oxidized form of xanthine dehydrogenase while calpain I or calpain II were ineffective. The possibility that an endogenous inhibitor prevented the proteolysis of XDH by calpain I or II was excluded by verifying that brain spectrin, a known calpain substrate, was degraded under the same incubation conditions. The results indicate that calpain is not likely to be responsible for the in vivo conversion of XD to XO under pathological conditions.

Authors+Show Affiliations

Center for the Neurobiology of Learning and Memory, University of California, Irvine 92717.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2557023

Citation

Stark, K, et al. "Proteolytic Conversion of Xanthine Dehydrogenase to Xanthine Oxidase: Evidence Against a Role for Calcium-activated Protease (calpain)." Biochemical and Biophysical Research Communications, vol. 165, no. 2, 1989, pp. 858-64.
Stark K, Seubert P, Lynch G, et al. Proteolytic conversion of xanthine dehydrogenase to xanthine oxidase: evidence against a role for calcium-activated protease (calpain). Biochem Biophys Res Commun. 1989;165(2):858-64.
Stark, K., Seubert, P., Lynch, G., & Baudry, M. (1989). Proteolytic conversion of xanthine dehydrogenase to xanthine oxidase: evidence against a role for calcium-activated protease (calpain). Biochemical and Biophysical Research Communications, 165(2), 858-64.
Stark K, et al. Proteolytic Conversion of Xanthine Dehydrogenase to Xanthine Oxidase: Evidence Against a Role for Calcium-activated Protease (calpain). Biochem Biophys Res Commun. 1989 Dec 15;165(2):858-64. PubMed PMID: 2557023.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Proteolytic conversion of xanthine dehydrogenase to xanthine oxidase: evidence against a role for calcium-activated protease (calpain). AU - Stark,K, AU - Seubert,P, AU - Lynch,G, AU - Baudry,M, PY - 1989/12/15/pubmed PY - 1989/12/15/medline PY - 1989/12/15/entrez SP - 858 EP - 64 JF - Biochemical and biophysical research communications JO - Biochem Biophys Res Commun VL - 165 IS - 2 N2 - The present study tested the hypothesis that calpain is responsible for the limited proteolytic conversion of xanthine dehydrogenase (XD) to xanthine oxidase (XO). We compared the effects of various proteases on the activity and molecular weight of a purified preparation of xanthine dehydrogenase from rat liver. In agreement with previous reports, trypsin treatment produced a complete conversion of XD to XO accompanied by a limited proteolysis of XDH from an Mr of 140 kD to an Mr of 90 kD. Treatment with calpain I or calpain II did not produce a conversion from XD to XO nor did it result in partial proteolysis of the enzyme. Similarly, trypsin treatment partially degraded a reversibly oxidized form of xanthine dehydrogenase while calpain I or calpain II were ineffective. The possibility that an endogenous inhibitor prevented the proteolysis of XDH by calpain I or II was excluded by verifying that brain spectrin, a known calpain substrate, was degraded under the same incubation conditions. The results indicate that calpain is not likely to be responsible for the in vivo conversion of XD to XO under pathological conditions. SN - 0006-291X UR - https://www.unboundmedicine.com/medline/citation/2557023/Proteolytic_conversion_of_xanthine_dehydrogenase_to_xanthine_oxidase:_evidence_against_a_role_for_calcium_activated_protease__calpain__ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006-291X(89)80045-2 DB - PRIME DP - Unbound Medicine ER -