zym ology , ▁a ▁protein - dis ulf ide ▁re duct ase ▁() ▁is ▁an ▁en zym e ▁that ▁catal y zes ▁the ▁chemical ▁reaction ▁ ▁protein ▁d ith i ol ▁+ ▁N AD ( P )+ ▁ ▁protein ▁dis ulf ide ▁+ ▁N AD ( P ) H ▁+ ▁H + ▁ ▁The ▁ 3 ▁substr ates ▁of ▁this ▁en zym e ▁are ▁protein ▁d ith i ol , ▁N AD + , ▁and ▁N AD P + , ▁whereas ▁its ▁ 4 ▁products ▁are ▁protein ▁dis ulf ide , ▁N AD H , ▁N AD PH , ▁and ▁H + . ▁ ▁This ▁en zym e ▁belongs ▁to ▁the ▁family ▁of ▁ox id ored uct ases , ▁specifically ▁those ▁acting ▁on ▁a ▁sul fur ▁group ▁of ▁don ors ▁with ▁N AD + ▁or ▁N AD P + ▁as ▁accept or . ▁ ▁The ▁system atic ▁name ▁of ▁this ▁en zym e ▁class ▁is ▁protein - d ith i ol : N AD ( P )+ ▁ox id ored uct ase . ▁Other ▁names ▁in ▁common ▁use ▁include ▁protein ▁dis ul ph ide ▁re duct ase , ▁ins ul in - gl ut ath ione ▁trans h ydro gen ase , ▁dis ulf ide ▁re duct ase , ▁and ▁N AD ( P ) H 2 : prote in - dis ulf ide ▁ox id ored uct ase . ▁ ▁Struct ural ▁studies ▁ ▁As ▁of ▁late ▁ 2 0 0 7 , ▁ 8 ▁structures ▁have ▁been ▁solved ▁for ▁this ▁class