Medium chain fatty acids as specific substrates for diglyceride acyltransferase in cultured hepatocytes.

N Mayorek,J Bar-Tana

doi:10.1016/s0021-9258(18)32291-9

Abstract

The fatty acyl substrate specificity for de novo diglyceride, triglyceride, and phospholipid synthesis in cultured hepatocytes was evaluated. The fatty acyl availability for diglyceride and phospholipid synthesis is restricted to fatty acids longer than myristic acid with octanoic and decanoic acids being excluded. On the other hand, octanoic and decanoic acids may serve as substrates for the diglyceride acyltransferase. Dodecanoic acid appears to occupy an intermediate position between medium and long chain fatty acids with respect to its availability as substrate for the esterification sites concerned. The availability of octanoate as a specific substrate for the diglyceride acyltransferase reaction in cultured hepatocytes enables the measurement of this activity in situ under conditions of overall triglyceride synthesis.

Highlights

Preparation of Cultured Hepatocytes-Hepatocytes essentially according to Berry and Friend [9]
Three esterification steps are involved in the synthesis of triglycerides: a-glycerophosphate esterification catalyzed by a-glycerophosphate acyltransferase (EC 2.3.1.15), lysophostimes with Hank's saline and the final cell suspension was counted in a hemocytometer
F-10 medium containing 10% horse serum, 10% fetalcalf serum, 100 phatidate esterification catalyzed by 1-acyl glycerophosphate pg/ml of streptomycin sulfate and 100 units/ml of penicillin G. 90 acyltransferase, and diglyceride esterification catalyzed by diglyceride acyltransferase (EC 2.3.1.20)

Summary

RESULTS

(Darmstadt, Germany). Collagenase was from Worthington (Freehold, NJ). Ham F-10 medium, horse serum, and fetal calf serum were The fattyacyl substrate specificity for de MUO diglyceride, from Grand Island Biological Company (Grand Island, NY). Tissue triglyceride, and phospholipid synthesis was evaluated in cultured hepatocytes by following the incorporation of radioac- This is an Open Access article under the CC BY license.

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DISCUSSION