Question

Discuss the following as to their effects on the phase transition temps (Tm) of a pure phospholipid vesiclewith C-14 (myristoyl) saturated chains.

a) addition of divalent metal cations, b)cholesterol, c) phosphatidylserine (C-18 saturated chains), d) phosphatidylcholine (C-18 monounsaturated chains)

Answer 1

Myristic acid or myristol is a saturated fatty acid with 14 carbons and as a constituent of dimyristoyl phosphatidylcholine is anticipated to play a part in van der Waals and hydrophobic interactions. At a particular Tm (temperature), these forces are strong are sufficient to produce neighboring instructions in a bilayer of the phospholipid.

a. The divalent cations such as CA2+ and Mg2+, act together with the negatively stimulating phosphate group and therefore alleviate bilayers and raise the temperature.

b. The cholesterol cannot change the temperature, still, it widens the phase transition. Being a molecule of lipid, it can take part in van der Waals and hydrophobic interactions. Above the dimyristoyl phosphatidylcholine Tm, cholesterol alleviates interactions, on the other hand, below the Tm, it hinders with the stuffing of dimyristoyl phosphatidylcholine.

c. The stearoyl phosphatidylserine consists of stearic acid with 18-carbon, completely saturated fatty acid, which supposed to contribute favorably in hydrophobic bonds and van der Waals interactions. Its slightly bigger chain length might trouble the vesicles geometry. Also, the bigger chain and negatively-charged group head must raise Tm.