Figure 3.

Convergence of the AT-10 sequence using a stepwise strategy. Based on the compositional analysis data that indicated the presence of three ±Ds, one ±4 and one ±7 disaccharide units for the decasaccharide, 320 possible sequences can be constructed, considering all possible permutations. The number of possible sequences equals ⁵C₃ (arrange 3 Ds in five positions) multiplied by ²C₁ (arrange the four in the remaining two positions) * 2⁴ (to account for the epimeric state of the uronic acid at each of the four internal positions; the nonreducing end uronic acid contains a Δ^4,5 bond from heparinase degradation) = 10 × 2 × 16 = 320. Application of experimental constraints to eliminate prospective solutions from the master list of 320 possible sequences results in convergence to the final sequence. Shown in the boxes at the left is the number of sequences that satisfy the experimental constraints. The boxes on the right show the sequences that satisfy the experimental constraints along with the possible fragments formed for the masses shown in parentheses at the top.