02205nas a2200241   4500008004100000022001400041245009500055210006900150260000800219300001200227490000700239520141000246653002001656653002301676653001201699653002201711100002301733700002301756700002301779700001501802700002501817856012101842       2025                        eng d  a1572-388700aCharacterization of S-homocysteinylation of Human Insulin and Its Implications in Diabetes0 aCharacterization of Shomocysteinylation of Human Insulin and Its  cOCT  a598-6100 v443 a<p>
	Homocysteine thiolactone is a reactive thiol known for its interaction with various proteins. Nevertheless, there exists a paucity of information concerning the interaction between homocysteine thiolactone and human insulin, particularly regarding the mechanism by which homocysteine facilitates the reduction of disulfide bonds within insulin. In the present study, we have elucidated the binding sites of homocysteine to the cysteine residues (A6-B7 and A20-B19) that are implicated in the formation of intermolecular disulfide bonds in insulin through an in vitro reaction analyzed via LC-ESI MS/MS. This results in a reduction of disulfide bonds linking the A and B chains, which was corroborated by MALDI-TOF-MS and ESI-MS analysis. The secondary structure of insulin is affected by this modification, as evidenced by circular dichroism spectroscopy. In-silico studies also show that homocysteine affects the insulin structure. A glucose uptake assay conducted in Chinese hamster ovary (CHO) cells that stably express the insulin receptor revealed that HC-modified insulin is less effective in inducing glucose uptake compared to native insulin, suggesting that HC-induced structural modifications in insulin influence functional activity. This study provides insight into the HC-induced structural and functional changes in insulin and discusses the consequent implications for diabetes.</p>
10aDisulfide bonds10aHomocysteinylation10ainsulin10aMass spectrometry1 aSheikh, Amreen, B.1 aJathar, Swaraj, M.1 aTammara, Vaishnavi1 aDas, Atanu1 aKulkarni, Mahesh, J.  uhttps://library.ncl.res.in/content/characterization-s-homocysteinylation-human-insulin-and-its-implications-diabetes