Literature summary for 4.4.1.20 extracted from

Nicholson, D.W.; Klemba, M.W.; Rasper, D.M.; Metters, K.M.; Zamboni, R.J.
Purification of human leukotriene C4 synthase from dimethylsulfoxide-differentiated U937 cells (1992), Eur. J. Biochem., 209, 725-734.

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General Stability

General Stability	Organism
partially purified enzyme requires substrate stabilization for long-term storage	Homo sapiens
reduced glutathione irreversibly inactivates the enzyme when present during freeze/thaw cycles and storage at concentrations above 5 mM	Homo sapiens

Inhibitors

Inhibitors	Comment	Organism	Structure
Co2+	-	Homo sapiens
KCl	0.5 mM, about 25% inhibition	Homo sapiens
leukotriene C2	IC50: 0.0011 mM	Homo sapiens
leukotriene C4	end product inhibition	Homo sapiens
leukotriene D4	-	Homo sapiens
leukotriene E4	-	Homo sapiens
NaCl	0.5 mM, about 25% inhibition	Homo sapiens

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.0166	-	leukotriene A4	-	Homo sapiens

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Ca2+	stimulates	Homo sapiens
Mg2+	30 mM, 1.8fold stimulation of partially purified enzyme	Homo sapiens

Organism

Organism	UniProt	Comment	Textmining
Homo sapiens	-	-	-

Purification (Commentary)

Purification (Comment)	Organism
-	Homo sapiens

Source Tissue

Source Tissue	Comment	Organism	Textmining
U-937 cell	monocytic leukemia cell line	Homo sapiens	-
U-937 cell	dimethylsulfoxide-differentiated U937 cells	Homo sapiens	-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
1.74	-	-	Homo sapiens

Storage Stability

Storage Stability	Organism
-80°C, in presence of 2-4 mM glutathione, stable for up to 1 year	Homo sapiens

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
leukotriene A4 + glutathione	-	Homo sapiens	leukotriene C4 + H2O	-	?

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
4	-	t1/2: 18 h	Homo sapiens
25	-	t1/2: 18 h	Homo sapiens

Ki Value [mM]

Ki Value [mM]	Ki Value maximum [mM]	Inhibitor	Comment	Organism	Structure
0.00036	-	leukotriene C2	-	Homo sapiens

IC50 Value

IC50 Value	IC50 Value Maximum	Comment	Organism	Inhibitor	Structure
0.0011	-	IC50: 0.0011 mM	Homo sapiens	leukotriene C2

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Release 2023.1 (January 2023)