The reduction of serum albumin, insulin and some simple disulphides by glutathione

Chemie und Biochemie Des Disulfidaustausches

“…Eine der Disulfidbindung benachbarte negative Ladung behindert den Thiol-Disulfidaustausch infolge Abstossung der RS--1onen durch Coulombkrafte. Die Reaktionsgeschwindigkeit von reduziertem Glutathion mit Dicarboxyathyldisulfid bei pH = 7.4 ist weit geringer als mit Cystamin oder L-Cystinylbis-valin, welche eine positiv geladene NHs +-Gruppe besitzen (27). Die Bestandigkeit der Disulfide gegenuber einem Angriff der Mercaptidionen des Cysteins nimmt in der Reihenfolge Glutathion > Cystin > Dithioglykolsaure ab (6).…”

Studies of interaction between insulin and glutathione using electrospray ionization mass spectrometry

“…Among them, the interactions of GSH and proteins play significant biological roles in cells including the formation of the mitotic apparatus during cell division and regulation of protein functions and protection of irreversible oxidation of proteins . Therefore, many proteins have been investigated to react with GSH in vitro for the better understanding of mechanisms of interactions of GSH and proteins, for example, serum albumin, bovine pancreatic ribonuclease, eye‐lens protein γ‐crystallin and cytochrome c …”

“…It has been postulated that GSH plays an important role in degradation or secretion of insulin, which has been extensively studied in vivo or in vitro . Direct in vitro interactions between insulin and GSH have been reported that GSH can break insulin into A and B chains by reduction of the disulfide bridges . Hird investigated the enzymic reduction of insulin by GSH and found that this reaction was slow when insulin was in the native state and speeded up after insulin was partly digested by proteolytic enzymes .…”

“…[3,4] Among them, the interactions of GSH and proteins play significant biological roles in cells including the formation of the mitotic apparatus during cell division [5,6] and regulation of protein functions and protection of irreversible oxidation of proteins. [7][8][9] Therefore, many proteins have been investigated to react with GSH in vitro [10][11][12][13][14][15][16][17][18][19][20]23] for the better understanding of mechanisms of interactions of GSH and proteins, for example, serum albumin, [12][13][14] bovine pancreatic ribonuclease, [15,16] eye-lens protein g-crystallin [18,19] and cytochrome c. [20] Insulin is a small globular protein to regulate energy storage and glucose metabolism in the body. It is synthesized in the pancreatic b-cells and causes cells in the liver, muscle and fat tissue to take up glucose from blood, storing it as glycogen in the liver and muscle.…”

“…[10,12,24,25] Hird investigated the enzymic reduction of insulin by GSH and found that this reaction was slow when insulin was in the native state and speeded up after insulin was partly digested by proteolytic enzymes. [12] Rafter found that an aggregate of insulin was formed when it was incubated with GSH [24] and Taniguchi and co-workers reported that insulin aggregation can be promoted by protein disulfide isomerase. [26] Alai and Fenselau demonstrated that insulinglutathione mixed disulfides were formed when insulin was incubated with GSH.…”