Affiliations: MRF Biochemistry Laboratory, Department of Surgery,
University of the Witwatersrand, Johannesburg, South Africa
Note: [] Address for correspondence: M.M.J. Oosthuizen, Clinical
Biochemistry Institute, PO Box 73231, Fairland, Johannesburg, 2030, South
Africa. Tel.: +27 11 6792447; Fax: +27 11 4750020; E-mail: [email protected] or
[email protected]
Abstract: Hepatoproliferin (HPF) was purified from regenerating rat livers as
an oligomeric entity (big-HPF) from which the monomeric form (small-HPF) could
be obtained using disaggregating conditions. By using a solid-phase
ion-exchange method, small-HPF was forced to dissociate into two charged ionic
species, namely norepinephrine (NE) and a sulfonated disaccharide with a
molecular structure consisting of D-glucuronic acid bound to glucosamine
2,6-disulfate by a β-glycosidic linkage having a
β, 1 → 4 configuration. Monomeric
HPF stemmed from the formation of three electrostatic bonds between the
protonated amine groups of three norepinephrines, of which two bind to the
deprotonated sulfonic groups of glucosamine 2,6-disulfate and one to the
deprotonated carboxylic group of glucuronic acid, to constitute a tightly
associated complex with a molecular mass of 1046 Da. This represents one of the
two purified isoforms of small-HPF. The other isoform, which has a lower
molecular mass of 877 Da, lack one NE, leaving the weaker carboxylic group of
glucuronic acid unoccupied, to constitute a more acidic form of HPF.
