Characterization of digoxigenin derivatives of human coagulation factors VIIa and X by electrospray mass spectrometry and enzyme kinetics.

Abstract

Digoxigenin ester (Dig) derivatives of coagulation factors VIIa and X facilitate staining studies to localize tissue factor activity in human atherosclerotic plaques. The larger the number of attached Dig units the easier it is to form highly visual stains. Electrospray ionization was used to characterize the Dig derivatives, as a function of excess derivatization reagent, to determine the optimal derivatives, i.e. the highest number of Dig units attached with the product still retaining enzymatic activity. The enzymatic activity of factor VIIa derivatized at 50-fold Dig excess (with 28, 34, 48 or 52 Dig units attached, masses to 79 kDa) remained the same as that of native factor VIIa. In contrast, the enzymatic activity of factor X derivatives diminished above 15-fold Dig excess (15 Dig units attached, mass 65.6 kDa). The distribution of derivatized lysine, histidine, arginine, tryptophan and tyrosine residues was estimated for several possible configurations.

• Authors: S V Thiruvikraman, J Roboz, T Wang, L Ma, G Seaman, A Guha
• Journal: Rapid communications in mass spectrometry : RCM (Rapid Commun Mass Spectrom) Vol. 10 Issue 11 Pg. 1367-70 ( 1996) ISSN: 0951-4198 [Print] England
• PMID: 8805845 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Amino Acids
• Indicators and Reagents
• Factor X
• Peptide Hydrolases
• Factor VIIa
• Digoxigenin

Topics

• Amino Acids (chemistry)
• Digoxigenin (chemistry)
• Factor VIIa (chemistry)
• Factor X (chemistry)
• Humans
• Indicators and Reagents
• Kinetics
• Mass Spectrometry
• Molecular Weight
• Peptide Hydrolases