Vitamin K2

维生素 K2

Place · Level 3

和 K1 是姐妹 · 把钙送进骨头 · 把钙挡在血管外 · 和 D 是一队的

Connected to · 5

synergy · 1

Vitamin D
D imports calcium; K2 routes it to bone, not arteries.

cofactor · 2

Bone
K2 carboxylates osteocalcin's glutamate residues into Gla — only then can it grip calcium. Un-carboxylated, the protein osteoblasts secrete is just a rope that can't hold on.
Osteoporosis
K2 governs where calcium goes: osteocalcin and matrix Gla protein both need gamma-carboxylation to work — the first clamps calcium into bone, the second keeps it out of the arterial wall. The mechanism is clear; the fracture-endpoint trial evidence is still early.

regulates · 1

Calcium
K2 routes calcium: activates osteocalcin (into bone) and MGP (out of arteries).

contrast · 1

Vitamin K1
Same naphthoquinone core, all the difference is in the tail: K1 goes to the liver to activate clotting factors II/VII/IX/X, K2 runs the osteocalcin and MGP route that decides where calcium ends up. One digit apart in the name, different jobs entirely.

K1 vs K2

Stop 1/6

K1 与 K2 · 姐妹分工

Vitamin K is a family that shares the same core (2-methyl-1,4-naphthoquinone head) but differs in tail length:

K1 (phylloquinone): single isoprenoid side chain, comes from leafy greens — it's literally part of the chlorophyll synthesis machinery. The liver takes it up to synthesize clotting factors II / VII / IX / X (γ-carboxylated so they can bind Ca²⁺ and start coagulation). Healthy people rarely lack K1 — leafy greens are everywhere.K2 (menaquinones, MK-n): multi-isoprenoid side chain where n is the unit count, commonly MK-4 through MK-13. Sources are fermented foods and gut microbial conversion. K2 routes to bone and blood vessels — the lead character of extra-hepatic vitamin K-dependent proteins (VKDPs).K3 (menadione): synthetic form without a side chain; hepatotoxic, so not usable as a human supplement — only animal feed and research.
So today's discussion of 'K2 prevents osteoporosis and arterial calcification' is almost never about coagulation — that's K1's territory.

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Educational content, not medical advice — consult a clinician.

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