Chinese Journal of Physiology

22 H. WU anp T. T. CHEN

the same conditions remains clear.** This shows that the albumin has undergone a change,—corresponding to the change is acid- and basebinding power expressed by the horizontal portion of the curves in figs. 9 and 10.

The effect of acid on sheep’s serum albumin in the cold is very slow. A 4per cent solution was mixed with an equal volume of N/10 HCl. After 24 hours the acid-binding power was measured at different reactions as described above for egg albumin and no change was detected. Addition of sodium sulphate to make a concentration of 20 per cent, however, produced some turbidity. Probably denaturation will occur on longer standing.

TABLE 9,

Effect of denaturation and coagulation on acid-binding power of serum albumin 20 cc of 0.65 per cent serum albumin solution+graded amounts of N/10 HCl or N/10 NaOH,

Before heating | After heating | No. N/10 HCl | N/10 HCl | | pH of pH or | pH of or N/20 NaCl) solution | difference N/10 NaOH) solution N/10 NaOH} added | or from added | | added | suspension) control cc ce cc 1 1.8 HCl 277 | 138 NaOH 0.9 4.12 0.07 2 1.5 | 1.0 1.5 4.14 0.09 3 1.2 | 0.7 211 4,13 0.08 4 0.9 O-4 2,7 4.14 0,09 a 0.7 | 0.2 3.1 4,19 O.1+ 6* 0.5 | 0.0 3.5 4.14 0,09 pe 0,8 0.2 HCl 3,9 4.10 0.05 3* 0.2 0.3 3.5 3.99 —0.06 Om 0.1 5.37 0.4 3.0 3.88 —0.17 10* 0,0 5,82 0.5 3.5 3.88 —0.17 11* 0,05 NaOH 0.55 34 3.93 —0.12 12 0.1 0.6 3.3 4,09 0.04 13 0,2 0.7 3.1 4.17 0,12 14 0.3 | 0.8 2.9 4.18 0.18 15 0.8 8.30 | 1.0 2.5 4.26 0.21 Unheated | | control 0.8 3.5 4,08 een

*Solutions show turbidity or precipitate after heating.

**Wu and Yen used sodium sulphate to promote flocculation of denatured albumins in their study (7), but through an oversight this fact was not mentioned,