TABLE 2.

Composite titration data for native and DNase-treated MVsa

Ligand classbMean pKacMean LT (μM/mg [dry wt])dProposed functional group
n15.48 (4.8-6.0)0.138 (45)Carboxyl
n26.91 (6.8-7.1)0.098 (32)Phosphate
n38.32 (8.2-8.4)0.070 (23)Amine
d15.18 (4.4-6.1)0.305 (38.5)Carboxyl
d26.90 (6.5-7.2)0.242 (30.5)Phosphate
d37.94 (7.8-9.0)0.246 (31)Amine
  • a The total available surface ligand concentrations for native and DNase-treated MVs were 0.306 and 0.793 μM/mg (dry weight), respectively (DNase/native ratio of 2.5). A ratiometric comparison of DNase-treated to native MVs indicated values of 2.2 (d1/n1), 2.5 (d2/n2), and 3.5 (d3/n3). Native MVs contributed 8% (wt/wt) of the total ligand concentration of the matrix material. Data were obtained from titration analysis of three independent samples.

  • b Based on pKa clusters in Fig. 5A and B.

  • c Values in parentheses represent ranges for given pKa clusters. Mean pKa values were estimated using a weighted mean calculation, with the corresponding available surface ligand concentration as the weighting factor.

  • d LT refers to site density (μM/mg [dry weight]). Values in parentheses represent the percent contribution of any functional group to the sample's total ligand concentration.