TRIGLYCERIDES AND FATTY ACIDS 111 



states that the oxygen which reacts with carotene is derived from some in- 

 termediate which is produced during the; peroxidation of the unsaturated 

 fat. The early work on Hpoxidase has been reviewed by SiiUmani^- and by 

 Jezeski;'^^ a comprehensive summary is that of Bergstrom and Holman.^^* 



(b) Distribution of Lipoxidase. Lipoxidase is widely distributed in the 

 plant kingdom. Thus, as has already been reported, lipoxidase occurs in 

 soybeans,'^'' white lupine,'**^ alfalfa,i^2,i83 ^j^(j potatoes;'^^ in addition, lipoxi- 

 dase has been detected in the seeds of a variety of legumes,^^^ in radishes,^^^ 

 in soybean meal preparations, ^^^ and in a number of species of beans and 

 peas.^^^ Siillman'^^ likewise reported the presence of this enzyme in a num- 

 ber of plant tissues. According to Van Fleet-""'-"* the lipoxidase content is 

 high at the seedling stage in plants grown on an alkaline medium. Lip- 

 oxidase is activated in areas in the plant which are neutral or alkaline, where 

 water loss has occurred, and below injured surfaces. The lipoxidase con- 

 tent has been sho^vn to decrease in germinating soybeans by the second day 

 after planthig, simultaneously with a reduction in the linoleate and linole- 

 nate contents. 



In contradistinction to the results on plant tissues, the misaturated fat 

 oxidases are not so widely distributed in animal tissues. It is also micer- 

 tain whether or not the enzyme is similar to lipoxidase. Although Banks^"^ 

 described a heat-labile system in herring muscle which stimulated rancidity 

 in fat, the active substance was later shown to involve hemin (hematin) 

 proteins;^"^'^"^ the action was quite different from that of hpoxidase. A 

 rancidity-provoking enzymic action in pig muscle^"^ was later proved to be 

 due to its hemoglobin and myoglobin content. 2"® An unsaturated fat oxi- 

 dase has been reported in rat liver and in rat gastric mucosa, ^"^ as well as in 



"2 H. Siillman, Fermentforschung, 17, 610-631 (1945). 



"3 J. J. Jezeski, Trans. Am. Assoc. Cereal Chemists, 5, 37-49 (1947); Chem. Abst., 4I, 

 4933 (1947). 



18^ S. Bergstrom and R. T. Holman, Advances in Enzymol., 8, 425-457 (1948). 



195 V. A. Kirsanova, Biokhimiya, 3, 191-200 (1938); Chem. Abst., 33, 8640 (1939); 

 Chimie & Industrie, 4I, 984 (1939). 



"6 H. H. Strain, J. Am. Chem. Soc, 63, 3542 (1941). 



1" R. J. Sumner and D. K. Tressler, Ind. Eng. Chem., 35, 921 (1943). 



198 R. Reiser and G. S. Traps, J. Assoc. Offic. Agr. Chemists, 26, 180-194 (1943). 



199 H. SuUman, Experientia, 1, 323-324 (1945). 



200 D. S. Van Fleet, Am. J. Botany, 29, 747-755 (1942). 

 »! D. S. Van Fleet, /. Am. Chem. Soc., 65, 740 (1943). 



202 A. Banks, /. Soc. Chem. Ind., 56, 13-15T (1937). 



203 A. Banks, /. Soc. Chem. Ind., 63, 8-13 (1944). 



^^ A. Banks, Personal communication (1947); cited by S. Bergstrom and R. T. 

 Holman, Advances in Enzymol., 8, 425-457 (1948), p. 443. 

 206 C. H. Lea, /. Soc. Chem. Ind., 56, 376-380T (1937). 



206 B. M. Watts and D.-H. Peng, /. Biol. Chem., 170, 441-453 (1947). 



207 E. L. Hove, Science, 98, 433-434 (1943). 



