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Literature summary for 1.14.19.20 extracted from

  • Kawata, S.; Traskos, J.M.; Gaylor, J.L.
    Microsomal enzymes of cholesterol biosynthesis from lanosterol. Purification and characterization of DELTA 7-sterol 5-desaturase of rat liver microsomes (1985), J. Biol. Chem., 260, 6609-6617.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
squalene and sterol carrier protein 2fold stimulation of enzyme activity in microsomes, stimulation is lower if microsomes are pretreated with phospholipase A2, acetone powder, 0.05% sodium deoxycholate or 0.2% Triton X-100 Rattus norvegicus

General Stability

General Stability Organism
extremely labile Rattus norvegicus

Inhibitors

Inhibitors Comment Organism Structure
1,10-phenanthroline 0.5 mM, 74% inhibition Rattus norvegicus
4,5-dihydroxy-1,3-benzene-disulfonic acid trivial name tiron, 0.5 mM, 80% inhibition Rattus norvegicus
bathophenanthroline 0.5 mM, 71% inhibition Rattus norvegicus
CN- 0.5 mM, 95% inhibition Rattus norvegicus
dithiothreitol 1.0 mM, 55% inhibition Rattus norvegicus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0357
-
5alpha-Cholest-7-en-3beta-ol reconstituted enzyme system consisting of: cytochrome b5, cytochrome b5 reductase and egg lecithin liposomes Rattus norvegicus

Localization

Localization Comment Organism GeneOntology No. Textmining
microsome
-
Rattus norvegicus
-
-

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ Rattus norvegicus cholesterol biosynthesis cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
-
?

Organism

Organism UniProt Comment Textmining
Rattus norvegicus
-
multienzyme system
-

Purification (Commentary)

Purification (Comment) Organism
-
Rattus norvegicus

Source Tissue

Source Tissue Comment Organism Textmining
liver
-
Rattus norvegicus
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
0.0079
-
-
Rattus norvegicus

Storage Stability

Storage Stability Organism
0°C, 24 h, 30% loss of activity Rattus norvegicus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ i.e. lathosterol Rattus norvegicus cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
-
?
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ enzyme is rather a mixed function oxidase which requires O2 and NAD(P)H for activity, than a dehydrogenase Rattus norvegicus cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
-
?
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ NADPH, 40% of activity with NADH Rattus norvegicus cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
-
?
5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ cholesterol biosynthesis Rattus norvegicus cholesta-5,7-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O
-
?

Cofactor

Cofactor Comment Organism Structure
cytochrome b5 required as electron carrier Rattus norvegicus
NAD(P)H
-
Rattus norvegicus