Table 2. Substitution frequency of isoleucine for other amina acids in the separated a and g chains of human hemoqlobin. Substitution frequency (Xx 107°) ample rxposure Globin? Pre-a a Pre-g B Expected value” 8A 69 R 12.93 7.61 2.35 40.36 12.42 15.71 Z24R 175 R 13.45 4.27 1.25 59.42 7.12 13.93 35R 175 R 5.19 c 4.34 c 8.32 6.33 71R 175 R 8.29 C 5.27 c 13.54 9.41 836 OR 2.45 Cc 2.05 c 4.4) 3.23 8670 OR 2.12 1.75 1.99 10.81 3.40 4.53 868) OR 4.35 5.57 1.76 8.69 5.04 4,34 “values reported in Table 1. Values expected when the Pp percertace G of each fraction and its substitution frequency are considered in the total. Ae om “The substitution frequency in this fraction was not determined; the quantity of polypeptide in this fraction represented less than 55 of total.