Transformation of LTA4 to LTC4

Return to overview

Leukotriene C4 synthase (LTC4S) transforms LTA4 into LTC4. This reaction involves the conjugation of the LTA4 epoxide and glutathione.

Reaction

Chemical equation

$LTA4 \rightleftharpoons LTC4$

Rate equation

Parameters

K_ms

Literature Values

Value	Units	Species	Notes	Weight	Reference
0.3 ± 0.06	mM	Human	Expression Vector: E. Coli. Enzyme: Wild Type hLTC4S pH:7.8 Temperature:20 °C	256
3.00E-02 ± 1.00E-02	mM	Human	Expression Vector: E Coli Enzyme: Wild type LTC4S pH: 7.8 Temperature: 37 °C	1024

Description of the LTC4S Kms distribution

Mode (mM)	Confidence Interval	Location parameter (µ)	Scale parameter (σ)
3.15E-02	7.18E+00	-2.83E+00	7.90E-01

The estimated probability distribution for LTC4S Kms. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

K_mp

Description of the LTC4S Kmp distribution

Mode (mM)	Location parameter (µ)	Scale parameter (σ)
3.18E-02	-2.82E+00	7.92E-01

The estimated probability distribution for LTC4S Kmp. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

k_cat

Literature Values

Value	Units	Species	Notes	Weight	Reference
702	per minute	Human	Expression Vector: E. Coli. Enzyme: Wild Type hLTC4S pH:7.8 Temperature:20 °C	256
1560 ± 240	per minute	Human	Expression Vector: E Coli Enzyme: Wild type LTC4S pH: 7.8 Temperature: 37 °C	1024

Description of the LTC4S kcat distribution

Mode (min-1)	Confidence Interval	Location parameter (µ)	Scale parameter (σ)
1.47E+03	1.42E+00	7.40E+00	3.29E-01

The estimated probability distribution for LTC4S kcat. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

Enzyme concentration

To convert the enzyme concentration from ppm to mM, the following equation was used.

Literature Values

Value	Units	Species	Notes	Weight	Reference
26.8	$ppm$	Human	Expression Vector: Lung Enzyme: LTC4S pH: 7.5 Temperature: 37 °C	1024
33.0	$ppm$	Human	Expression Vector: Esophagus Enzyme: LTC4S pH: 7.5 Temperature: 37 °C	2048
13.9	$ppm$	Human	Expression Vector: Adrenal Gland Enzyme: LTC4S pH: 7.5 Temperature: 37 °C	1024

Description of the LTC4S concentration distribution

Mode (mM)	Mode (ppm)	Confidence Interval	Location parameter (µ)	Scale parameter (σ)
2.90E+01	1.60E-04	1.44E+00	3.49E+00	3.46E-01

The estimated probability distribution for LTC4S concentration. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

K_eq

Literature Values

Gibbs Free Energy Change	Units	Species	Notes	Weight	Reference
9.934128	kcal/mol	Not stated	Estimated Enzyme: LTC4S Substrate: LTA4 Product: LTC4 pH: 7.3 ionic strength: 0.25	64

Description of the LTC4S Keq distribution

Mode (mM)	Confidence Interval	Location parameter (µ)	Scale parameter (σ)
5.13E-08	1.00E+01	-1.60E+01	8.90E-01

The estimated probability distribution for LTC4S Keq. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.