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The worldwide importance of human hepatitis B virus infection and the toll it takes in chronic liver disease, cirrhosis and hepatocarcinoma, make it imperative that a vaccine be developed for worldwide application. Human hepatitis B vaccines are presently prepared using hepatitis B surface antigen (HBsAg) that is purified from the plasma of human carriers(More)
The hepatitis B (HB) virus preS2 + 2 polypeptide (the M or middle envelope polypeptide) is N-glycosylated at the N4 residue of the preS2 domain when expressed in recombinant yeast. Hyperglycosylation at this amino acid residue (the addition of a large number of mannose residues to the core oligosaccharide), which occurs in common yeast strains, results in(More)
An artificial capillary system was devised for growth of hepatoma cells that yields very high titers of hepatitis B surface antigen (HBsAg). High yield of antigen was facilitated by slowing cellular metabolism through reduction of incubation temperature and addition of 0.1 mM caffeine. Deletion of serum from the medium did not reduce the yield of antigen.(More)
Six enzymes involved in the conversion of aspartate to threonine have been extracted from Escherichia coli and separated from each other. Two of these enzymes, aspartokinase and homoserine dehydrogenase, have also been partially purified from Rhodopseudomonas spheroides. In an attempt to determine whether small changes in the kinetic properties of(More)
Hepatitis B surface antigen (HBsAg) has been extracted from yeast cells that produce HBsAg. These cells contain the gene for surface antigen carried on a plasmid that replicates in the cells. Analysis of the yeast-derived HBsAg by sucrose gradient centrifugation and by polyacrylamide gel electrophoresis shows that the antigen that is initially released from(More)
A population of procollagen molecules has been isolated from the culture medium of a clonal line of calf dermatosparactic cells and shown to have the amino-acid composition, physical properties, and molecular structure consistent with collagen precursors. Although this procollagen population shares immunologic determinants with the procollagen obtained from(More)
Human plasma alpha-galactosidase A (alpha-D-galactoside galactohydrolase, EC 3.2.1.22) was purified 7000-fold over plasma levels from Cohn Fraction IV-1. The yield per kg starting material averaged 11 000 units (nmol galactose liberated per h) and the specific activity was about 600 units per mg protein with 4-methylumbelliferyl-alpha-D-galactoside. The(More)