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The isocitrate dehydrogenase phosphorylation cycle: Regulation and enzymology
Author(s) -
Laporte David C.
Publication year - 1993
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240510104
Subject(s) - phosphorylation , isocitrate dehydrogenase , biochemistry , serine , dephosphorylation , biology , glyoxylate cycle , phosphatase , kinase , protein phosphorylation , microbiology and biotechnology , chemistry , enzyme , protein kinase a
Isocitrate dehydrogenase (IDH) of Escherichia coli is regulated by phosphorylation and dephosphorylation. This phosphorylation cycle controls the flow of isocitrate through the glyoxylate bypass, a pathway which bypasses the CO 2 evolving steps of the Krebs' cycle. IDH is phosphorylated at a single serine which resides in its active site. Phosphorylation blocks isocitrate binding, thereby inactivating IDH. The IDH phosphorylation cycle is catalyzed by a bifunctional protein kinase/phosphatase. The kinase and phosphatase reactions appear to be catalyzed at the same site and may share some catalytic steps. A variety of approaches have been used to examine the IDH phosphorylation cycle in the intact organism. The picture which has emerged is one of an exquisitely sensitive and flexible system which is capable of adapting efficiently to the environment both inside and outside the cell. © 1993 Wiley‐Liss, Inc.