DYNAMIC ASPECTS — AMINO ACID POOL TURNOVER 
NI 
on 
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ON THE METABOLIC IMPORTANCE OF AMINO ACID-LIPID 
COMPLEXES 
RICHARD W. HENDLER 
National Heart Institute, National Institutes of Health, Bethesda, Md. (U.S.A.) 
Although amino acids have been observed in lipid fractions for many years!, they 
have been regarded generally as contaminants which the investigator should try to 
remove by further purification. During a study of the formation of the proteins of 
the hen oviduct from radioactive amino acids, it was learned that an extremely non- 
polar form of the amino acid was rapidly formed?. It was found that protein synthesis 
was markedly inhibited by low concentrations of lecithinase A (crotoxyn) and other 
lipolytic agents, and that CoA and cytidine triphosphate exerted a stimulatory effect. 
Further studies with the hen oviduct have shown that amino acids can enter and leave 
these lipid complexes at a high rate when compared to their entry and exit from 
associations with nucleic acids and their entry into protein’. It was found* that each 
SOF Lipids of supernatant 
---- 2,4-Dinitrophenol 
Control 
Counts /min 

O 200 . 400 600 800 
Alumina- silica chromatography 
Fig. 1. The abscissas designate volume of effluent in ml. Lipid fraction was obtained from 4 g 
hen oviduct after incubation for 15 min with “C-labeled algal protein hydrolyzate prior to homo- 
genization and separation into cell debris and supernatant fractions. 5 g of adsorbent in a column 
of 1 cm dia. was used. The 2,4-dinitrophenol (10-* M/) was present during a 15-min preincubation 
prior to addition of radioactive amino acids and subsequent 15-min incubation. Solvent changes 
were as follows: hexane—chloroform (1 : 1) to 60 ml effluent, hexane—chloroform (1 : 2) to roo ml, 
hexane—chloroform (1 : 4) to 150ml, chloroform to 210 ml. Methanol—chloroform (1 : 99) to 
490 ml, methanol-chloroform (4:96) to 590ml, methanol—chloroform (8 : 92) to 625 ml, 
methanol—chloroform (15 : 85) to 685 ml, methanol-chloroform (25 : 75) 730ml methanol— 
chloroform (36 : 65) to 785 ml, methanol-chloroform (50 : 50) to 840 ml and methanol to end. 
* This material was presented at a meeting of the Faraday Society, March 1960, University of 
Reading, Reading (Great Britain). 
References p. 758 
