EMBRYONIC HEMOGLOBIN SYNTHESIS
101
of 5-day embryo erythrocytes subjected to starch-gel electrophoresis, the
third component representing only 5-10% of the total Hb (Fig. 1).
About 30% of the total Hb was diffuse (migrating anodally) and may
represent some of the minor adult components. The three types of embryonic Hb were examined by "fingerprinting'' and by separating subunits by electrophoresis at low pH. Two of the Hb's had both A and B
subunits different from the adult A and B subunits. The three Hb's
possessed one subunit in common (the A class), while the second subunit
(B class) differed in all three Hb types (Fig. 2). The B subunit displayed
some heterogeneity after starch-gel electrophoresis, and the three Hb
types also showed some heterogeneity after separation by polyacrylamide-gel electrophoresis; three types of Hb are probably a minimum
number for the 5-day embryo.
2. Frogs
a. Adults. Hb of a large number of amphibians, especially Anura, is
known to be heterogeneous (Gratzer and Allison, 1960). Riggs et al.
(1964) showed frog Hb has a marked tendency to polymerize, and this
must be controlled and monitored to evaluate the extent and nature of
heterogeneity. Frieden and his collaborators have investigated the Hb
of some frogs (1961). Electrophoresis and sedimentation analysis of
Rana grylio revealed 2 components (Trader et al., 1963). Frieden (1961)
obtained evidence for multiple Hb's in other amphibia. Baglioni and
Sparks (1963) examined Hb of Rana catesbeiana by a number of techniques. Four Hb types were consistently observed in adults after starchgel electrophoresis, and one of these types may consist of polymerized
Hb. The Hb's were purified by starch-block electrophoresis and "fingerprinted"; the "fingerprint" patterns were quite similar, but did display
some minor differences. Globin subunit constitution was analyzed by
electrophoresis in 8 M urea, and 2 subunits were demonstrated for each
Hb type. One of the Hb types possessed a subunit very different from
the standard types, but other differences were not observed. Hamada
et al. (1964) have also examined adult Rana catesbeiana. Three Hb types
were isolated by chromatography on DEAE cellulose. The Hb appeared
homogeneous, however, by electrophoresis and sedimentation, and only
glycine is found as the N-terminal amino acid. Moss and Ingram (1965)
have carried out a recent interesting study on synthesis of Hb in tadpoles,
and during the course of this work examined adult Hb by polyacrylamide-gel electrophoresis at low pH in the presence of urea. The Hb
of the adult formed one very prominent band and one faint band.
b. Tadpoles. Early amphibian embryos have not been carefully examined for the types of Hb they contain, but premetamorphic tadpoles have
been examined. The major conclusion, that the tadpole Hb is quite
101
of 5-day embryo erythrocytes subjected to starch-gel electrophoresis, the
third component representing only 5-10% of the total Hb (Fig. 1).
About 30% of the total Hb was diffuse (migrating anodally) and may
represent some of the minor adult components. The three types of embryonic Hb were examined by "fingerprinting'' and by separating subunits by electrophoresis at low pH. Two of the Hb's had both A and B
subunits different from the adult A and B subunits. The three Hb's
possessed one subunit in common (the A class), while the second subunit
(B class) differed in all three Hb types (Fig. 2). The B subunit displayed
some heterogeneity after starch-gel electrophoresis, and the three Hb
types also showed some heterogeneity after separation by polyacrylamide-gel electrophoresis; three types of Hb are probably a minimum
number for the 5-day embryo.
2. Frogs
a. Adults. Hb of a large number of amphibians, especially Anura, is
known to be heterogeneous (Gratzer and Allison, 1960). Riggs et al.
(1964) showed frog Hb has a marked tendency to polymerize, and this
must be controlled and monitored to evaluate the extent and nature of
heterogeneity. Frieden and his collaborators have investigated the Hb
of some frogs (1961). Electrophoresis and sedimentation analysis of
Rana grylio revealed 2 components (Trader et al., 1963). Frieden (1961)
obtained evidence for multiple Hb's in other amphibia. Baglioni and
Sparks (1963) examined Hb of Rana catesbeiana by a number of techniques. Four Hb types were consistently observed in adults after starchgel electrophoresis, and one of these types may consist of polymerized
Hb. The Hb's were purified by starch-block electrophoresis and "fingerprinted"; the "fingerprint" patterns were quite similar, but did display
some minor differences. Globin subunit constitution was analyzed by
electrophoresis in 8 M urea, and 2 subunits were demonstrated for each
Hb type. One of the Hb types possessed a subunit very different from
the standard types, but other differences were not observed. Hamada
et al. (1964) have also examined adult Rana catesbeiana. Three Hb types
were isolated by chromatography on DEAE cellulose. The Hb appeared
homogeneous, however, by electrophoresis and sedimentation, and only
glycine is found as the N-terminal amino acid. Moss and Ingram (1965)
have carried out a recent interesting study on synthesis of Hb in tadpoles,
and during the course of this work examined adult Hb by polyacrylamide-gel electrophoresis at low pH in the presence of urea. The Hb
of the adult formed one very prominent band and one faint band.
b. Tadpoles. Early amphibian embryos have not been carefully examined for the types of Hb they contain, but premetamorphic tadpoles have
been examined. The major conclusion, that the tadpole Hb is quite