242 P. SOUPART 
results of a detailed quantitative study on free amino acid composition of cat tissues 
by means of ion-exchange chromatography”. A similar study dealing with in- 
vertebrates’ tissues by means of microbiological methods** has been done by 
DucHATEAU AND FLORKIN, among their numerous studies of amino acids in inverte- 
brates. 
As pointed out by McMEnamy ef al.3! “understanding of the role of the blood in 
amino acid transport and metabolism requires information not only about the plasma 
concentration and turnover of these metabolites but also about their distribution 
between the plasma and the formed elements of the blood”. In man, as already 
stated, while the free amino acid content of the blood plasma has been extensively in- 
TABLE Vil 
FREE AMINO ACID CONCENTRATION IN PLASMA, ERYTHROCYTES, LEUCOCYTES AND PLATELETS 
Adult man. Values are expressed in umoles/too g of wet wt.*. 



Erythrocytes 
Amino acid Plasma** BUCS popes * Brg rs re 
Taurine 5 3 3.6 2003 2100 
Lysine 20 5 13.0 230 122 
Glycine 22 34 37 508 305 
Alanine 42 21 35 661 270 
Valine 27 2 33 375 150 
Leucine 14 2 40 630 188 
Isoleucine 7 0.3 4 290 120 
Serine 12 II 15 510 3605 
Threonine 13 4 16 340 155 
Phenylalanine 5 0.5 4 248 85 
Tyrosine 6 I 5 197 7 
Histidine 8 383) 14 63 31 
Arginine 10 fe) oO 33 53 
Aspartic acid 0.2 33 37 350 270 
Glutamic acid§ (5) (32) (32) (736) (316) 
Methionine 3 oO Traces 175 38 
Cystine 1/, II oO oO 37 oO 
Proline 22 2 17 210 102 

* Corrected for water content: plasma 92%, erythrocytes 65%, leucocytes 75%, platelets 87%. 
** Average concentration according to STEIN AND Moore”. 
*** Correction for diffusion losses based on results shown in Table IX. 
§ Approximate values. 
vestigated, there are rather few studies to be found on free-amino acid content of 
blood cells, except that of LyER on erythrocytes", that of NouR-ELDIN AND WILKIN- 
son* and of RousErR** on leucocytes, and the very recent one of MCMENAmy ef al.*?, 
the latter study dealing with the simultaneous determination of unbound amino 
acids in plasma, erythrocytes, leucocytes and urine of normal subjects. Two other 
papers, dealing with a limited number of amino acids only, have also been published 
by CHRISTENSEN et al.47 and by JOHNSON AND BERGEIM‘*®. SCHRAM AND HUBINONT 
have communicated preliminary results obtained by ion-exchange chromatography 
on the distribution of free amino acids between erythrocytes, leucocytes and plate- 
References p. 261/262 
