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Titolo:
ON THE MECHANISM OF INACTIVATION OF ACTIVE PAPAIN BY ASCORBIC-ACID INTHE PRESENCE OF CUPRIC IONS
Autore:
KANAZAWA H; FUJIMOTO S; OHARA A;
Indirizzi:
KYOTO PHARMACEUT UNIV,5 NAKAUCHI CHO,YAMASHINA KU KYOTO 607 JAPAN
Titolo Testata:
Biological & pharmaceutical bulletin
fascicolo: 6, volume: 17, anno: 1994,
pagine: 789 - 793
SICI:
0918-6158(1994)17:6<789:OTMOIO>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
CATALYZED OXIDATION; DEPENDENT FORMATION; HYDROXYL RADICALS; OXYGEN RADICALS; AUTOXIDATION; CONSEQUENCES; PROTEINS; SYSTEMS; DAMAGE;
Keywords:
SITE-SPECIFIC INACTIVATION; CUPRIC ION ASCORBIC ACID SYSTEM; ACTIVE PAPAIN; HYDROXYL RADICAL; ACTIVE SULFHYDRYL GROUP;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
H. Kanazawa et al., "ON THE MECHANISM OF INACTIVATION OF ACTIVE PAPAIN BY ASCORBIC-ACID INTHE PRESENCE OF CUPRIC IONS", Biological & pharmaceutical bulletin, 17(6), 1994, pp. 789-793

Abstract

An inactivation mechanism of active papain (EC 3.4.22.2) by the Cu2+-ascorbic acid (AsA) system was examined. Incubation of active papain, which contains an active sulfhydryl (SH) group, with the Cu2+-AsA system under aerobic conditions resulted in an irreversible loss of enzymeactivity. The enzyme was not inactivated at a molar ratio of enzyme to Cu2+ of 1:<1, whereas at a molar ratio of 1:1-2, the extent of inactivation showed the same dependence on the extent of oxidation of AsA. Saturation kinetics were observed with respect to the concentration ofAsA. The degree of inactivation was dependent on the decrease in SH content of the enzyme. Catalase at a low concentration partially protected the enzyme from inactivation, but did not affect the oxidation of AsA. In addition, catalase at a high concentration completely protected both the enzyme from inactivation and AsA from oxidation. The present results suggest that an additional function of H2O2, besides producing hydroxyl radicals (.OH), is to promote the conversion of Cu+ into Cu2+, and that an active SH group of papain is site-specifically modified by the .OH, resulting in inactivation of the enzyme.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/03/20 alle ore 17:35:34