TABLE I 

 Methods for Determining PNA and DNA 



Fraction 



Description of procedure 



Phosphorus 

 compounds in fraction 



1. Procedure of Schmidt and Thannhauser^ 



Fresh Should be used immediately or stored at 



tissue —10°. All volumes should be at least 20 



times that of samples, and tissue should 

 be homogenized in ice-cold water. 

 I Ice-cold 5-10% trichloroacetic acid (TCA) 



or perchloric acid (PCA) extract. Extrac- 

 tion to be carried out rapidly and repeated 

 three times. 

 II Combined extracts of tissue residue by 80% 

 ethanol, ethanol, warm ethanol-chloro- 

 form (3:1), or ethanol-ether (1:1) and 

 ether. 



III Alkaline digest formed by overnight incu- 



bation in N NaOH or KOH at 37° of tissue 

 residue from II (1 ml. alkali per 100 mg. 

 fresh tissue). 



IV Supernatant formed by addition to III of 



HCl (to neutralize NaOH) and TCA or 

 PCA to give final concentration of 5-10%. 

 Precipitate centrifuged down at 0° and 

 washed twice with 5% TCA or PCA. 

 V Precipitate of inorganic PO4 from IV by 

 method of Delory^^ or Mathison.^^ 

 VI Precipitate from TCA or PCA treatment of 

 III. 

 VII Extract of VI with 5% TCA at 90° for 15 

 min. — two washings with 5% TCA. 



All acid-soluble com- 

 pounds 



Phospholipids 



PNA-P + DNA-P + con- 

 comitant (non-nucleo- 

 tide) P 



PNA-P + concomitant P 



"Phosphoprotein" or part 



of concomitant P 

 DNA-P (+ protein) 



DNA for ultraviolet ab- 

 sorption''* 



Fresh 

 tissue 

 I 



II 

 VIII 



IX 



2. Procedure of Schneider^ 

 As for procedure 1. 



As fbr procedure 1. 

 As for procedure 1. 

 Tissue residue. 



Extract of VIII with 5% TCA or 6% PCA 

 at 90° for 15 min. Combined with two 

 washings with acid. 



Insoluble residue after acid extraction of 

 VIII. 



Acid-soluble compounds 



Phospholipid 



PNA-P + DNA-P + con- 

 comitant 



PNA-P + DNA-P + some 

 concomitant P 



"Phosphoprotein," P, 

 and residual concomi- 

 tant P 



3. Procedure of Ogur and Rosen^* 



Fresh 

 tissue 

 XI 



XII 



XIII 



XIV 

 XV 



XVI 



Kept in 70-95% ethanol at 0°, and homogen- 

 ized prior to extraction. 



Extract of homogenate with 70% ethanol at 

 4°, washed again with 70% ethanol con- 

 taining 0.1% PCA at 4°. 



Extract of tissue residue with boiling eth- 

 anol ether (3:1). Repeated, and extracts 

 combined. 



Cold, rapid extraction of tissue residue 

 from XII with 0.2 N PCA. Repeated, and 

 extracts combined. 



Tissue residue from XIII. 



Extract of XIV with N PCA for 18 hr. at 4°. 

 Two washings with N PCA. Extracts 

 combined. 



Extract of tissue residue from XV with 0.5 

 A^ PCA at 70° for 20 min. Process re- 

 peated, and extracts combined. 



Alcohol-soluble com- 

 pounds 



Alcohol-ether soluble 

 compounds 



Acid-soluble compounds 



PNA-P + DNA-P + con- 

 comitant P 

 PNA-P 



DNA-P + concomitant P 



