Name: China Supplier Hot Sale High Purity Phosphatidylserine CAS 51446-62-9
Brand: Wuhan Fortuna Chemical Co., Ltd.

Phosphatidylserine (PS) is a crucial glycerophospholipid, a major component of cell membranes, particularly concentrated in the inner leaflet of the plasma membrane in eukaryotic cells. Its chemical structure defines its properties and functions:

Core Structure:

sn-1 position: Typically a saturated fatty acid (e.g., stearic acid, 18:0).
sn-2 position: Typically an unsaturated fatty acid (e.g., oleic acid 18:1, arachidonic acid 20:4). The specific fatty acids vary, influencing membrane fluidity.

Glycerol Backbone: A 3-carbon molecule (sn-glycerol-3-phosphate).
Two Fatty Acyl Chains: Esterified to the sn-1 and sn-2 hydroxyl groups of the glycerol backbone. These are hydrophobic "tails".
Phosphate Group: Attached to the sn-3 hydroxyl group of glycerol via a phosphodiester bond. This forms the "linker".
Serine Headgroup: The amino acid L-serine is attached via a phosphodiester bond to the phosphate group. This is the hydrophilic, polar "head".
Chemical Formula:

The general formula for a PS molecule with specific fatty acids is C₄₂H₈₂NO₁₀P (for 1-stearoyl-2-oleoyl-PS, a common form).
The core structure without specifying fatty acids is often represented as C₃H₈NO₁₀P (for the headgroup + glycerol + phosphate), but this ignores the variable fatty acid chains.
Key Chemical Features:

The phosphate group (pKa ~2-3) is fully deprotonated (PO₄²⁻).
The carboxyl group of serine (pKa ~4.5) is deprotonated (COO⁻).
The amino group of serine (pKa ~9-10) is protonated (NH₃⁺).
This gives the PS headgroup a net charge of -1 (PO₄⁻ + COO⁻ + NH₃⁺ = -1 overall). It's a highly negatively charged (anionic) phospholipid.

Amphipathic: Combines hydrophobic tails (fatty acids) and a hydrophilic head (phosphate + serine). This is essential for forming lipid bilayers.
Chiral Center: The carbon at position 2 of the glycerol backbone (sn-2 carbon) is chiral. Naturally occurring PS uses the sn-glycerol-3-phosphate configuration.
Anionic Headgroup: At physiological pH (~7.4):
Biological Significance (Driven by Chemistry):

Apoptosis (Programmed Cell Death): Signals phagocytes to engulf the dying cell.
Blood Clotting: Provides a surface for coagulation factor complexes.

Membrane Asymmetry: Its concentration on the inner leaflet is maintained by specific enzymes (flippases). Loss of this asymmetry (exposure of PS on the outer leaflet) is a key signal for processes like:
Protein Recruitment: Its negative charge attracts and activates numerous proteins with polybasic domains (e.g., protein kinase C (PKC), Raf-1, K-Ras, synaptotagmin).
Cell Signaling: Involved in activating key signaling pathways (e.g., Akt/PKB, MAPK).
Membrane Fusion: Important in processes like neurotransmitter release at synapses.

Summary Structure:

O - P - O - CH₂ - CH - COO⁻

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O⁻ O⁻ ⁺NH₃

Glycerol Backbone (C1 & C2 esterified to Fatty Acid Chains)

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R1 R2 (Hydrophobic Fatty Acid Tails)

O=P-O-: Phosphate Group
-CH₂-CH-COO⁻: Serine Headgroup (L-Serine)
⁺NH₃
Glycerol Backbone: The central 3-carbon chain.
R1 & R2: Long hydrocarbon chains of the fatty acids (e.g., -C₁₇H₃₅ for stearate, -C₁₇H₃₃ for oleate).

Phosphatidylserine's unique chemical structure, particularly its serine headgroup and resulting negative charge, underpins its vital roles in membrane biology, signaling, and cellular recognition.