There are very few reports on the activity values of aspartate aminotransferase(GOT) and alanine amir?otransferase (GPT) in oxyhemoglobin and their successivefractional precipitation. Especially, no papers have been published to deal with avianoxyhemoglobin in detail.In the present report, an ingenious method was proposed for separation of suchtransaminases as generally called "forward (F)-GOT, reverse (R)-GOT, F-GPT, andR-GPT." Some of the transaminases in adult chicken oxyhemoglobin could be fraction-ated into a very confined fraction.The results obtained are summarized as follows.In addition, the solution of adult chicken oxyhemoglobin used in this experimentwas prepared by a method proposed by the author18). The activity values of the fractionsseparated and their source sample were determined by the same substrates as usedfor the previous studies on transaminase activities in adult chicken blood plasma.l. The technique used for the fractionation of transaminases in adult chickenoxyhemoglobin depended for its principle upon Cohn and Oncleys method3, 9). Ac-cordingly, except for a slight modification on the adjustment of protein content, all theprocedures and the method of naming fractions used in this technique were the same asthose reported by those authors3?9).By using this method, all the fractions separated from adult chicken oxyhemoglobinnumbered twelve which fell under five large divisions. Tables l and 2 shows the relation-ships between these fractions and their transaminase activities.An important problem, however, is to select confining transaminases that will workto the highest possible degree. For the solution of this problem, it seems that the follow-ing fractions may have an advantage. 2. It appeared that component 2-c, its subtraction, and some conaponents of the4th grou pin adult chicken oxyhemoglobin might be related to some extent to the carriersof transaminases.As for R-GPT, it was possible that a subtraction of component 2-c might act as anR-GPT, which would be recovered from fractions IV-6 and IV-7. On the other hand, component 2-c might act as one of the transaminases which catalyze the substrates ofboth R-GOT and R-GPT and would be recovered from fraction V and its subtraction.Component 4-d of relative position 29 in the middle of component 4-d conjugatedwas present in fractions III, III-0, and III-2, 3. It was useful to activate the substrates ofboth R-GOT and R-GPT. From this, it seemed probable that some of the R-GOTcarriers might belong to the sarne type as R-GPT related. However, when the relativepositions of two components in the 4-d position in fractions IV-4 and IV-5, which werecatalyzed by the substrates of both transaminases for use in determination of F-GOT andF-GPT activity values, were examined, they were not the same as that of component 4-d.just described, but were arranged at both ends of that component. The relative positionsof the two components were found to be 28 and 30, respectively. These findings sug-gest that component 4-d may have been conjugated in adult chicken oxyhemoglobin andconsist of at least 3 components.The most important point, however, is that neither a subfraction of componentt 2-cnor component 4-d conjugated has anything in common with blood plasma. In contrastto blood plasma, this result seems to be an important fact to explain the distribution ofthe active fragment of transaminase in adult chicken oxyhemoglobin. In a report tocome, an attempt will be made to clarify a difference in chemical properties of the proteincontained in the transaminases bearing the samenames between oxyhmoglobin and bloodplasma.