Chinese Journal of Physiology

24 H. WU anp T. T. CHEN

Change in pH|

Cc fy HC! addede—'+3 Co +X naOHaddea

Fig. 10. Change in base-binding power of serum albumin on denaturation

and coagulation,

Denaturation. and coagulation of hemoglobin.—Table 11 and fig. 11 show the effect of heat denaturation and coagulation of oxyhemoglobin. The similarity between egg albumin (fig. 5) and hemoglobin is apparent. The effect of denaturation of hemoglobin by acid or alkali in the cold is also similar to that on egg albumin, the only difference being that the former is much more sensitive, especially towards acids. Hence in the more acid solution the difference in reaction between the denatured and the ‘‘control” could not be detected as the hemoglobin in the “control” also underwent denaturation before the measurement could be made. The change of pH with time of an acid hemoglobin solution with an initial reaction of pH 3.8 is shown in table 12. At an initial reaction of pH 3.0 the denaturation was practically instantaneous and no control

could be prepared.

Lewis’ failure to detect any difference between denatured and natural hemoglobin is to us quite puzzling. Most of the points which he determined lay outside of the pH range 5-8, and in view of the ease with which hemoglobin is denatured by dilute acids and alkalies, the