Literature summary for 1.5.1.20 extracted from

Engbersen, A.M.T.; Franken, D.G.; Boers, G.H.J.; Stevens, E.M.B.; Trijbels, F.J.M.; Blom, H.J.
Thermolabile 5,10-methylenetetrahydrofolate reductase as a cause of mild hyperhomocysteinemia (1995), Am. J. Hum. Genet., 56, 142-150.

Search for more literature for 1.5.1.20

Application

Application	Comment	Organism
medicine	deficiency and thermolability of enzyme as cause of mild homocysteinemia with premature vascular disease	Homo sapiens

Inhibitors

Inhibitors	Comment	Organism	Structure
S-adenosylmethionine	-	Homo sapiens

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.019	-	5-methyltetrahydrofolate	-	Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
5,10-methylenetetrahydrofolate + reduced acceptor	Homo sapiens	homocysteine metabolism	5-methyltetrahydrofolate + oxidized acceptor	5-methyltetrahydrofolate is the main form of circulating folate	?
5,10-methylenetetrahydrofolate + reduced acceptor	Homo sapiens	physiological direction is the 5-methyltetrahydrofolate formation	5-methyltetrahydrofolate + oxidized acceptor	5-methyltetrahydrofolate is the main form of circulating folate	?
5,10-methylenetetrahydrofolate + reduced acceptor	Homo sapiens	remethylation of homocysteine to methionine	5-methyltetrahydrofolate + oxidized acceptor	5-methyltetrahydrofolate is the main form of circulating folate	?

Organism

Organism	UniProt	Comment	Textmining
Homo sapiens	-	-	-

Source Tissue

Source Tissue	Comment	Organism	Textmining
lymphocyte	-	Homo sapiens	-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
additional information	-	values of healthy and homocysteinemic humans before and after heat inactivation, specific activity of thermolabile variant of enzyme in homozygotes is 50% of normal enzyme	Homo sapiens

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
5,10-methylenetetrahydrofolate + reduced acceptor	reverse reaction: menadione as electron acceptor	Homo sapiens	5-methyltetrahydrofolate + oxidized acceptor	-	?
5,10-methylenetetrahydrofolate + reduced acceptor	homocysteine metabolism	Homo sapiens	5-methyltetrahydrofolate + oxidized acceptor	5-methyltetrahydrofolate is the main form of circulating folate	?
5,10-methylenetetrahydrofolate + reduced acceptor	physiological direction is the 5-methyltetrahydrofolate formation	Homo sapiens	5-methyltetrahydrofolate + oxidized acceptor	5-methyltetrahydrofolate is the main form of circulating folate	?
5,10-methylenetetrahydrofolate + reduced acceptor	remethylation of homocysteine to methionine	Homo sapiens	5-methyltetrahydrofolate + oxidized acceptor	5-methyltetrahydrofolate is the main form of circulating folate	?

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
37	-	assay at	Homo sapiens

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
additional information	-	activity of enzyme from healthy and homocysteinemic humans after heat inactivation, the latter with a more thermolabile enzyme: residual activity in homozygotes is lower than 30% compared with 50% in control subjects	Homo sapiens
40	-	5 min, 17% loss of activity	Homo sapiens
46	-	5 min, 53% loss of activity	Homo sapiens
49	-	5 min, 70% loss of activity	Homo sapiens

Cofactor

Cofactor	Comment	Organism	Structure
FAD	enzyme activity depends on the concentration of its cofactor FAD: maximum activity at 0.05 mM FAD	Homo sapiens

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Release 2023.1 (January 2023)