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Subunits asymmetry in the ternary complex of lamb liver 6-phosphogluconate dehydrogenase detected by a NADP analogue.
Biochim Biophys Acta. 1992 Oct 20; 1159(3):262-6.BB

Abstract

Incubation of lamb liver 6-phosphogluconate dehydrogenase, a dimeric enzyme with periodate-oxidized NADP causes the inactivation of the enzyme due to the covalent binding of 2 mol of inhibitor/mol of dimer. In the presence of substrate, the inactivation is faster and is almost complete after the labelling of only one subunit. These results not only confirm the hypothesis of a 'half-of-the-sites' mechanism of action of the enzyme, but also suggest that the formation of the ternary complex (enzyme-substrate-coenzyme) in one subunit causes a conformational change that makes the other subunit unable to bind the coenzyme (and even the adenylic part of it) and, thus, this subunit becomes inactive. It appears that while one subunit catalyses the oxidation of 6-phosphogluconate the other is inactive in this reaction.

Authors+Show Affiliations

Istituto di Chimica Biologica, Universita Ferrara, Italy.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

1390931

Citation

Hanau, S, et al. "Subunits Asymmetry in the Ternary Complex of Lamb Liver 6-phosphogluconate Dehydrogenase Detected By a NADP Analogue." Biochimica Et Biophysica Acta, vol. 1159, no. 3, 1992, pp. 262-6.
Hanau S, Dallocchio F, Rippa M. Subunits asymmetry in the ternary complex of lamb liver 6-phosphogluconate dehydrogenase detected by a NADP analogue. Biochim Biophys Acta. 1992;1159(3):262-6.
Hanau, S., Dallocchio, F., & Rippa, M. (1992). Subunits asymmetry in the ternary complex of lamb liver 6-phosphogluconate dehydrogenase detected by a NADP analogue. Biochimica Et Biophysica Acta, 1159(3), 262-6.
Hanau S, Dallocchio F, Rippa M. Subunits Asymmetry in the Ternary Complex of Lamb Liver 6-phosphogluconate Dehydrogenase Detected By a NADP Analogue. Biochim Biophys Acta. 1992 Oct 20;1159(3):262-6. PubMed PMID: 1390931.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Subunits asymmetry in the ternary complex of lamb liver 6-phosphogluconate dehydrogenase detected by a NADP analogue. AU - Hanau,S, AU - Dallocchio,F, AU - Rippa,M, PY - 1992/10/20/pubmed PY - 1992/10/20/medline PY - 1992/10/20/entrez SP - 262 EP - 6 JF - Biochimica et biophysica acta JO - Biochim. Biophys. Acta VL - 1159 IS - 3 N2 - Incubation of lamb liver 6-phosphogluconate dehydrogenase, a dimeric enzyme with periodate-oxidized NADP causes the inactivation of the enzyme due to the covalent binding of 2 mol of inhibitor/mol of dimer. In the presence of substrate, the inactivation is faster and is almost complete after the labelling of only one subunit. These results not only confirm the hypothesis of a 'half-of-the-sites' mechanism of action of the enzyme, but also suggest that the formation of the ternary complex (enzyme-substrate-coenzyme) in one subunit causes a conformational change that makes the other subunit unable to bind the coenzyme (and even the adenylic part of it) and, thus, this subunit becomes inactive. It appears that while one subunit catalyses the oxidation of 6-phosphogluconate the other is inactive in this reaction. SN - 0006-3002 UR - https://www.unboundmedicine.com/medline/citation/1390931/Subunits_asymmetry_in_the_ternary_complex_of_lamb_liver_6_phosphogluconate_dehydrogenase_detected_by_a_NADP_analogue_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0167-4838(92)90054-H DB - PRIME DP - Unbound Medicine ER -