Oxidation of cysteine to cystine in Proinsulin

Stable Identifier
Reaction [transition]
Homo sapiens
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Cystine bonds are formed in Proinsulin-1 between cysteine residues 31 and 96, cysteine residues 43 and 109, and cysteine residues 95 and 100. Ero1-like alpha does not directly catalyze the oxidation of cysteines to cystine. Instead it maintains a suitably oxidizing environment for the reactions to occur . Though Ero1-like alpha can act via specific isomerases such as P4HB/PDI, there is currently no evidence that formation of cystine bonds in insulin requires a specific isomerase. Interestingly, even in beta cells of wild type animals, trace amounts of incorrectly bonded proinsulin can be detected. Thus, the formation of correct cystine bonds may involve a period of bond shuffling.

Literature References
PubMed ID Title Journal Year
12624089 In vitro refolding of human proinsulin. Kinetic intermediates, putative disulfide-forming pathway folding initiation site, and potential role of C-peptide in folding process

Feng, YM, Hua, QX, Min, CY, Weiss, MA, Qiao, ZS

J Biol Chem 2003
9631292 The role of assembly in insulin's biosynthesis

Steiner, D, Dodson, G

Curr Opin Struct Biol 1998
15096212 Unfolding of human proinsulin. Intermediates and possible role of its C-peptide in folding/unfolding

Feng, YM, Min, CY, Qiao, ZS

Eur J Biochem 2004
12590147 Role of the connecting peptide in insulin biosynthesis

Liu, M, Ramos-CastaƱeda, J, Arvan, P

J Biol Chem 2003
15705595 Proinsulin disulfide maturation and misfolding in the endoplasmic reticulum

Liu, M, Arvan, P, Li, Y, Cavener, D

J Biol Chem 2005
14744022 Role of disulfide bonds in the structure and activity of human insulin

Jang, SH, Chang, SG, Shin, HC, Choi, KD

Mol Cells 2003
Catalyst Activity

disulfide oxidoreductase activity of EROIL-like Proteins [endoplasmic reticulum lumen]

Orthologous Events
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