UU, UZ ve ZZ fenotipleri tespit edilmiştir. Bulgular sonucunda, en sık görülen fenotiplerin, katalaz enzim sisteminde % 63 oranında FS; karbonik anhidraz enzim sisteminde % 91.73 oranında II, proteaz inhibitör enzim sisteminde ise %16.07 oranında FU fenotipleri olduğu belirlendi. Bu üç sistem gen frekansları yönünden incelendiğinde; katalaz enzim sisteminde en yüksek gen frekansının S genine (0.69), karbonik anhidraz enzim sisteminde I genine (0.959) ve proteaz inhibitör enzim sisteminde U genine (0.357) ait olduğu tespit edilmiştir.Anahtar sözcükler: Arap atı, elektroforez, karbonik anhidraz, katalaz, proteaz inhibitör enzim sistemiThe electrophoretic investigation of erythrocyte catalase, carbonic anhydrase and plasma protease inhibitor enzyme systems belong to dam, sire and offspring in the purebred Arabian horses in Turkey Summary: In this study was examined catalase and carbonic anhydrase enzyme systems in 254 and proteas inhibitor enzyme system in 112 purebred Arabian horses. SS and FS phenotypes which belong to catalase enzyme system, EI, FI, II, IL phenotypes which belong to carbonic anhydrase enzyme system and FF, FG, FL, FS 2 , FU, FZ, GP, GQ, GR, GS 1 , GS 2 , GU, GZ, HL, HU, LL, LP, LS 1 , LZ, PS 1 , PU, PZ, S 1 S 1 , S 1 U, S 1 Z, S 2 U, S 2 Z, UU, UZ, ZZ phenotypes which belong to Pi were detected in Arabian horses that used in this study. The data of this study showed that the most commanly seen phenotypes in catalase enzyme systems were FS % 63, in carbonic anhydrase were II with % 91.73 and protease inhibitor enzyme system were FU with %16.07. When these three enzyme system were evaluated by means of gene frequencies, it was detected that the highest gene frequencies in catalase enzyme system belong to S gene (0.69), in carbonic anhydrase enzyme system belong to I gene (0.959) and protease inhibitor enzyme system belong to U gene (0.357).