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The effects of substrates, products and other ligands on the susceptibility of inositol monophosphatase to proteolysis by endoprotease lys‐C
Author(s) -
Gee N.S.,
Knowles M.R.,
McAllister G.,
Ragan C.I.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80770-4
Subject(s) - proteolysis , chemistry , biochemistry , enzyme
Inositol monophosphatase is cleaved by endoprotease lys‐C at a single site (Lys 36 —Ser 37 ). The rate of proteolysis is greatly reduced in the presence of substrate (D,L‐Ins(I)P) and Mg 2+ , and less so in the presence of P i and Mg 2+ , consistent with protection of the susceptible bond in the E—P or E·P i states of the enzyme. Potentiation by Li + of the protection afforded by a substrate analogue, 1 S ‐phosphoryloxy‐2 R ,4 S ‐dihydroxycyclohexane, and Mg 2+ supports the idea that Li + binds to the E—P state.