CROSS-LINKED GLOBULAR-PROTEINS - A NEW CL ASS OF SEMISYNTHETIC MACROMOLECULES - CHARACTERIZATION OF THEIR STRUCTURE IN SOLUTION FOR HYPERPOLYMERIC HEMOGLOBIN AND MYOGLOBIN BY MEANS OF SIZE-EXCLUSION CHROMATOGRAPHY, VISCOSIMETRY, OSMOMETRY AND LIGHT-SCATTERING
H. Potzschke et al., CROSS-LINKED GLOBULAR-PROTEINS - A NEW CL ASS OF SEMISYNTHETIC MACROMOLECULES - CHARACTERIZATION OF THEIR STRUCTURE IN SOLUTION FOR HYPERPOLYMERIC HEMOGLOBIN AND MYOGLOBIN BY MEANS OF SIZE-EXCLUSION CHROMATOGRAPHY, VISCOSIMETRY, OSMOMETRY AND LIGHT-SCATTERING, Macromolecular chemistry and physics, 197(4), 1996, pp. 1419-1437
Developing an artificial oxygen carrier for use in humans, we polymeri
ze native haemoglobin and myoglobin, using bifunctional, amino group s
pecific cross-linkers, to soluble, so-called hyperpolymers. These poly
mers, like other polymerized globular proteins, are members of a new c
lass of macromolecues which consist of macromolecular base units. They
all have, due to the mechanisms of the chemical reaction, broad distr
ibutions of molecular weights. Fractions of hyperpolymers of human hae
moglobin were obtained by employing preparative gel-permeation (size-e
xclusion) chromatography. The calibration curve of analytical gel-perm
eation chromatography (GPC) for haemoglobin hyperpolymers was determin
ed using mean molecular weights of some fractions, as assessed by osmo
metric and light scattering measurements. In analogy to native globula
r proteins, the calibration curve for haemoglobin polymers - within th
e range of molecular weights considered here, and within the experimen
tal accuracy - is a straight line. All fractions of haemoglobin polyme
rs were further characterized with the aid of calibrated analytical GP
C. Mean nonuniformity was about 0,6. The dependence of the logarithm o
f the intrinsic viscosity [eta] on the logarithm of the viscosity-aver
age molecular weight (M) over bar(eta) of the fractions (the curve in
the ''structure-in-solution diagram'') also is a straight line, which
is true for haemoglobin and for myoglobin polymers as well. Its first
derivative is the exponent a of the Mark-Houwink function; for haemogl
obin and myoglobin polymers the values are 0,39 and 0,46, respectively
. Haemoglobin and myoglobin hyperpolymers, as members of the new class
of polymers, both have a characteristic so-called ''structure-in-solu
tion diagram'', and a characteristic calibration curve in GPC. The spe
cial structure-in-solution of the polymer proteins is a novel molecula
r superstructure. The intrinsic viscosity for native myoglobin was fou
nd to be 3,5 mL/g.