Lanosterol !

Lanosterol is the first sterol of the pathway: it already has the four rings but carries three extra methyl groups.

Updated 2026-11-01

Loading the 3D model…

Key facts

Lanosterol synthase makes it from 2,3-oxidosqualene in one reaction that closes four rings.
It has 30 carbons; losing three methyls (C30 → C27) and shifting double bonds takes it to cholesterol in about twenty reactions.
The first, 14α-demethylation, is done by CYP51, the same enzyme azoles inhibit in fungi.

A steroid nucleus with an OH on C3, two methyls on C4 and one on C14, which cholesterol lacks.
Its name comes from lanolin, the wool grease where it was found.

Lanosterol synthase variants cause congenital cataracts; lanosterol has been studied to dissolve lens aggregates, with no clinical use yet.
Lanosterol promotes degradation of HMG-CoA reductase (feedback).

Think of the answer, then tap the question to see it.

Which enzyme makes lanosterol?

Lanosterol synthase (oxidosqualene cyclase), which cyclises 2,3-oxidosqualene.

How does lanosterol differ from cholesterol?

It has 30 carbons: three extra methyls (two on C4, one on C14) and different double bonds.

Which human enzyme of the lanosterol-to-cholesterol stretch resembles the azole target?

CYP51 (lanosterol 14α-demethylase); azoles mainly inhibit the fungal one.

Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.

Educational information, not medical advice. For any symptom, see a health professional.

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.