356 V. BLOOD LIPIDS 



and possibly by other unsaturated acids. Moreover, the presence of 

 various fatty acids in the medium increased the protective effect of serum 

 albumin against hemolysis, as determined by in vitro tests. Boyer et ah 32 

 demonstrated a protective action on the part of the albumin against hemoly- 

 sis due to sodium caprylate, although its beneficial effect was greater than 

 was predicted from the "combined caprylate" content of the medium. 



Boyer et al. 32 employed the ultrafiltration technic with considerable suc- 

 cess for the study of fatty acid binding by protein. These workers used 

 butyrate, caproate, caprylate, caprate, and acetyltryptophane, and the 

 work was later extended to include mandelate. 39 One can apply a simple 

 mass action expression to these data to obtain a quantitative interpretation 

 of the results. Moreover, this technic does not require as sensitive analyti- 

 cal procedures as do several of the other tests, since higher concentrations 

 of protein and anion are involved. 



Serum albumin, especially, appears to have a conspicuous ability to 

 bind anions. According to Teresi and Luck, 40,41 bovine serum albumin has 

 the capacity to bind 25 ions per mole in the case of the more strongly as- 

 sociated anions. In later experiments, 42 the mechanism of the combination 

 of fatty acids and serum albumin was investigated by means of carboxyl- 

 labeled d 4 fatty acids. It was found that there were two groups of binding 

 sites per protein molecule, each of which was characterized by its own par- 

 ticular binding constants. On the other hand, crystalline /3-lactoglobulin 43 

 was found to be able to bind only 2 ions per mole of fatty acids, while crys- 

 talline /3-amylase 43 appears to be devoid of any such capacity. These data 

 are in line with the classification of Klotz and Urquhart, 44 in which the rela- 

 tive binding power of protein is analyzed as follows: highest binding- 

 power, serum albumin and /3-lactoglobulin ; slight binding power, oval- 

 bumin and conalbumin; no binding power, pepsin, trypsin, chymotrypsin, 

 ribonuclease, and insulin. Also in line with the above findings, Davis and 

 Dubos 38 reported that the protective action of serum albumin against oleic 

 acid, as observed in the cultivation of tubercle bacilli, was shown to a slight 

 extent by jS-lactoglobulin, but was not exhibited by any other proteins 

 tested. Luck, 8 on the basis of the shift in absorption spectrum which occurs 

 when fatty acids are combined with serum albumin, believes that gelatin 

 and 7-globulin do not combine with fatty acids; finally, on the basis of 



39 J. M. Luck, J. Phys. & Colloid Chem., 51, 229-239 (1947). 



40 J. D. Teresi and J. M. Luck, J. Biol. Chem., 174, 653-661 (1948). 



41 J. D. Teresi and J. M. Luck, J. Biol. Chem., 177, 383 (1949). 



42 J. D. Teresi and J. M. Luck, «/. Biol. Chem., 194, 823-834 (1952). 



43 J. D. Teresi; cited by J. M. Luck, in Lipoproteins, General discussion Faraday 

 Soc, No. 6, 44-52, Aberdeen Univ. Press, Aberdeen, 1949, p. 48. 



44 I. M. Klotz, and J. M. Urquhart, J. Am. Chem. Soc, 71, 1597-1603 (1949). 



