[[[Types of Bonds]]
[[Rough Endoplasmic Reticulum (RER)]]
==Disulfide
Bonds/Bridges==
*OXIDATION of [[Cysteine]] [[amino acids]] residues
==Mechanism:== 1+2 4 5
*1)Two thiol residues are deprotonated
producing two cysteine thiolates
**Accomplished by enzymes such as
protein disulfide isomerase (PDI)
*2)Low molecular weight disulfide with
two respsective R groups
*3)Two electron oxidation reaction
*4)Mixed
Disulfide is formed by a two step reversible process
**thiol/disulfide
exchange reactions
**?Nucleophilic attack of one of the thiolates to one
of the sulfur atoms of the disulfide creating a Protein-S-Sd
*(R)-Sd-R
***Sd* is a sulfur from the Disulfide
***Sd* is positively charged due
to the extra bond occured by the thiolate
***The R group attached to the
Sd* is kicked out
***Because it is a “two step reversible process” it
sounds like an SN1-ish reaction
**Creating one of the thiolates to be
attached to the Disulfide kicking out one of its respective R groups
*5)Disulfide is formed by the nucleophilic attack of the other thiolate
to the closer disulfide S
====Additional Information:====
*[http://en.wikipedia.org/wiki/Disulfide_bond Wikipedia]
*[http://beck2.med.harvard.edu/protein_folding/protein_folding.htm
Harvard]
*[http://www.sciencedirect.com.ezproxy.lib.usf.edu/science?_ob=ArticleURL&_udi=B6T4X-4DHX08K-1&_user=2139826&_coverDate=01%2F01%2F2005&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000054278&_version=1&_urlVersion=0&_userid=2139826&md5=db75d4f4905ade8d2e75f9e9f4a67980&searchtype=a
quote taken from article Bulaj's Formation of disulfide bonds in
proteins and peptides] ]]
