Proinsulin binds zinc and calcium forming Proinsulin:zinc:calcium

Stable Identifier
Reaction [binding]
Homo sapiens
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In the presence of high concentrations of zinc and calcium, proinsulin spontaneously forms soluble complexes containing 6 molecules of proinsulin, 2 zinc ions, and 1 calcium ion. Zinc Transporters ZnT5, ZnT6, and ZnT7 are found in the membrane of the Golgi in pancreatic cells (and also in many other cell types). They play a role in maintaining the high zinc concentration in the Golgi lumen and thus catalyze the formation of the proinsulin-zinc-calcium complex. Other transporters, such as the newly identified ZnT9 and ZnT10, may also be involved but this is presently unknown.
Literature References
PubMed ID Title Journal Year
9631292 The role of assembly in insulin's biosynthesis

Steiner, D, Dodson, G

Curr Opin Struct Biol 1998
14704853 Overview of mammalian zinc transporters

Nagao, M, Sasaki, R, Yamaguchi-Iwai, Y, Kambe, T

Cell Mol Life Sci 2004
2669954 Comparison of solution structural flexibility and zinc binding domains for insulin, proinsulin, and miniproinsulin

Dunn, MF, Ko, HC, Kaarsholm, NC

Biochemistry 1989
16158220 Zinc-ligand interactions modulate assembly and stability of the insulin hexamer -- a review

Dunn, MF

Biometals 2005
10521251 Role of metal ions in the T- to R-allosteric transition in the insulin hexamer

Kadima, W

Biochemistry 1999
Orthologous Events
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