Ellman reported that DTNB quantitatively reacted with sulfhydryl compounds according to the following equation to form the aromatic thiol anion whose extinction coefficient was 13, 600/M/cm at 412mμ
We reexamined the stoichiometry of this reaction by measuring the response curves of glutathione or cysteine with DTNB and isolated all the reaction products on paper chromatograms and Sepnadex G-10 gel filtration. From the investigation of chemical properties of the produtcs, we concluded that the mixed disulfide formed according to Eq. 1 sub- sequently reacted with a second sulfhydryl compound to give another aromatic thiol anion in the following manner.

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A new enzymatic method is proposed for the determination of phospholipid in serum.
The principle of this method is as follows: Phospholipid is hybrolyzed into diglyceride and phosphorylcholine with phospholipase C. When treated with alkaline phosphatase, phosphorylcholine produced by hydrolysis of phospholipid liberates inorganic phosphate.
The amount of phospholipid is calculated according to a formula from the value of inorganic phosphate which is measured by the method of Fiske-Subbarow. The values of serum phospholipid determined with the proposed method were all correlated with those by the chemical method. The method also proved to be satisfactory in precision.
Since the enzymatic method is simpler and more specific for the measurement of phospholipid than the chemical method, the former method is suitable in estimating pho- spholipid in clinical laboratory.

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It was reported that starvation and alloxan treatment influenced the acetate metabolism in sheep liver slices, and relationships between the acetate metabolism and glycolisis changed following alloxan treatment. Further study was designed to elucidiate the relationships between the acetate metabolism and TCA cycle, and how the relationships were influenced by starvation and alloxan treatment. The following results were obtained in a study of the influence of citrate or succinate on the ¹⁴C-acetate metabolism and of acetate on the metabolism of ¹⁴C-citrate or-succinate in liver slices of normalily fed, starved and alloxan diabetic sheep.
In normal and starved conditions, transfer of ¹⁴C from ¹⁴C-acetate into CO2, cholesterol, triglyceride and phospholipid increased and the formation of ¹⁴C-glucose, -ketone bodies and NEFA from ¹⁴C-acetate decreasad by the addition of citrate or succinate. The formation of ¹⁴CO from ¹⁴C-citrate or-succinate increased and transfer of ¹⁴C from ¹⁴C-citrate or-succinate into glucose, ketone bodies, cholesterol, triglyceride and phospholipid decreased by the addition of acetate in nlrmal and starved sheep. Effects of citrate on the acetate metabolism and those of acetate on the citrate metabolism disappeared following alloxan treatmet. But effects of succinate on the acetate metabolism were observed in alloxan diabetes.
As mentilned above, citrate or succinate showed various effects on the acetate metabolism and also the acetate had various effects on the metabolism of citrate and succinate. The relationships betweentheacetate and succinate metabolisms changed due to alloxan treatment.

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A rapid and simplified method for arginase determination using unigraph paper is reported. The buffer pH, substrate clncentration, activator, incubation temperature, incubation time, linearity of the reaction, and reproducibility are examined.

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