Chinese Journal of Physiology

ACIN- AND BASE-BINDING POWER OF PROTEINS 25

hemoglobin in his controls might have been denatured by the added acid or alkali before the measurement of pH could be made. This is unquestionably the case in the more acid solutions.

TABLE 11,

Eifect of denaturation and coagulation on acid-binding power of oxyhemoglobin

20 cc 0.89 per cent oxyhemoglobin solution+graded amounts of N/10 HClor N/10 NaOH, i

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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 contro] | | | ce | ce ce | 1 1,5 HCl 3.85 0.7 NaOH 1.6 5.32 | 0,69 2 | 12 O04 22 5.19 | 0.56 3 | 0.8 0.0 3.0 5,12 0.49 4* | 0.5 0.8 HCl 3.0 497 | 0.84 5* 0.8 0.5 3.0 482 | 0,19 6* | O1 6.78 0,7 3.0 4,84 =0.29 ie | 0,0 0.8 3.0 461 | —0,12 8* 0.1 NaOH 0.9 2.8 4.39 ° | —0,2+ een Ors ell 2,4 4,92 | 0,29 10* | 0.6 123 2.0 4.97 | 0.3 b 1] | 0.8 1.6 14 5.01 0.38 2 | 452 2,0 0.6 6,11 0.45 13 15 10.05 2.3 0,0 6,14 0.51 Unheated | control 0.8 3.0 4.63

*Solutions show turbidity or precipitate after heating.

TABLE 12,

Change of pl of acid methemoglobin solution with time 100 cc of 1 per cent methomoglobin solution+4.8 cc N/10 HCl.

Time after mixing | 3.4 mi. | 9 mi, | 25.7 mi.| 71.7 mi,| Next morning | | | | pH | 38,82 3.86 | 9.93 3.99 4.17

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Coagulated hemoglobin could not be redissolved in such dilute acid and alkali solutions in the pH range 5 to 8, and the reaction of such a suspension is necessarily different from the control in which the natural