Pyridoxylation of the essential lysines in the heparin-binding site of bovine platelet factor 4.
The lysine residues of bovine platelet factor 4 essential to heparin-binding activity have been determined. The protein was labelled by pyridoxal 5$\sp\prime$-phosphate and reduced by sodium borohydride. Three moles of lysine residues are labelled per mole of platelet factor 4. This resulting modified protein exhibits a loss of affinity for heparin-agarose affinity columns. The identities of the three essential lysines have been established by pyridoxylation, proteolytic digestions, peptide mapping, amino acid analysis and partial amino acid sequencing. Lys-61, Lys-77 and Lys-80 are essential for platelet factor 4 binding to heparin; moreover, the binding of heparin to platelet factor 4 protects these three lysine residues from modification. Six corrections of the sequence from residues 44 to 83 of bovine platelet factor 4 have been made: threonine 49, leucine 57, lysine 60, arginine 72, leucine 79 and lysine 81 should be corrected to leucine 49, isoleucine 57, leucine 60, asparagine 72, isoleucine 79 and arginine 81. (Abstract shortened by UMI.)Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1991 .L385. Source: Masters Abstracts International, Volume: 31-01, page: 0311. Adviser: Lana Lee. Thesis (M.Sc.)--University of Windsor (Canada), 1991.
Networked Digital Library of Theses and Dissertations