Studies on Carboxypeptidase Digests of Human Hemoglobin

Spectrophotometric Titration Curves of Human Hemoglobin and Its Carboxypeptidase Digests*

“…The possibility remains that am and /3m are abnormal in another complex of hemoglobin. If they are abnormal in reduced hemoglobin, these side-chains play a role in the conformation change which accompanies oxygenation (heme-heme interaction, Haurowitz and Hardin, 1954), which is indeed a possibility suggested by the results of Antonini et al (1961). We have no data on reduced hemoglobin, and, as was explained above, our data give us no conclusive information about side-chains a14i and /9l45 in cyanide-methemoglobin because a conformational change may accompany the removal of these residues.…”

“…We have also digested human hemoglobin with both carboxypeptidases. When a digestion is performed with both enzymes present simultaneously (experiments 5 and 6 of Table I), proteolytic action exceeds the sum of the action of the separate enzymes, as was noted by Antonini et al (1961). In fact, the number of tyrosine residues removed approaches a limit of six residues pier molecule of hemoglobin.…”

“…Loss of a normal or of an abnormal tyrosine residue might then be taken as evidence of the state of the tyrosine which has been removed. Removal of tyrosines aHi and /3m has recently been performed by Antonini et al (1961). With carboxypeptidase A these authors selectively removed histidine 0m and tyrosine 0m and with carboxypeptidase B arginine aU2 and tyrosine am.…”

“…(CPA and CPB) were procured from Worthington Biochemicals, Freehold, N. J. B. Methods.-Carboxypeptidase digests of human hemoglobin (Antonini et al, 1961) were prepared by allowing a solution of carbon monoxide hemoglobin to which a certain amount of carboxypeptidase solution had been added (carboxypeptidase A in 10% LiCl, carboxypeptidase B in water) to react overnight at 30°a nd pH 8 in a carbon monoxide atmosphere. The resulting solution was passed through a column of Sephadex G-25, medium grade, and the effluent containing the proteins and that containing the amino acids were collected in separate vessels.…”

Μελετη Μεταφορας Και Αποδοσης Οξυγονου Σε Ασθενεις Με Αιμοσφαιρινοπαθεια Η Και F-Θαλασσαιμια

“…Οι πρωτοεμβρυονικές αιμοσφαιρίνες είναι η αιμοσφαιρίνη Gower 1, η Gower 2 και η Portlanó (σχήμα 1) και ανιχνεύονται μέχρι την 11 η -12 η εμβρυϊκή εβδομάδα (14,15,16). Η Gower 1 που αποτελείται από δύο αλυσίδες ζ και δύο αλυσίδες ε (ζ 2 ε 2 ), αποτελεί το 40% του συνόλου των αιμοσφαιρινών κατά την έκτη εβδομάδα, ενώ η Gower 2 αποτελείται από δύο α αλυσίδες και δύο ε (α 2 ε 2 ) και κατά την έκτη εβδομάδα αποτελεί το -2- (34,35,36,37,38,39,40). η-ι-ι-ι-ι-|-ι-π-τη-τ-ι-τ-ι-|-ι-τ-ι-τη-τ-ι-ι Hb <g/dl> ΣΧΗΜΑ 38: Συσχέτιση του 2.3DPG με το επίπεδο της Hb στην αιμοσφαιρινοπάθεια Η.…”