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We conclude that fructose-1,6-diphosphate, when given during early reperfusion, significantly improves recovery of both diastolic and systolic function in association with increased glucose uptake and higher phosphocreatine levels during reperfusion.

A kringle 5 domain fragment from human plasminogen has been investigated by 'H-NMR spectroscopy at 300 MHz and 620 MHz. The study focuses on the kringle 5 aromatic spectrum as aromatic side chains appear to mediate the binding of benzamidine. Spin-echo experiments and acidlbase-titration studies in conjunction with two-dimensional double-quantum and chemical-shift-correlated spectroscopies were used to identify individual spin systems. Sequence-specific assignments of aromatic resonances are derived from direct comparison of the kringle 5 spectrum with spectra of the homologous kringle 1 and kringle 4 domains of plasminogen. As previously observed for kringles 1 and 4, the pattern we detect for Tyr9 in kringle 5 reflects a slow conformational exchange between two states in equilibrium, one in which the Tyr9 ring is freely mobile and one in which its flip dynamics are constrained. Proton Overhauser experiments in lHzO and in 2 H z 0 have been used to probe aromatic ring interactions and to identify residues which are part of the hydrophobic core centered at the Leu46 side chain. Overall, the data indicate a strong structural homology among the three plasminogen kringles.In 1975 Magnusson and collaborators [l] proposed the term 'kringle' to identify a triple cystine polypeptide loop pattern, of about 10 kDa, which was observed in two proteolytic fragments of prothrombin. As determined by the Danish investigators, the kringle structure is characterized by disulfide bridges linking Cys residue pairs 1 -6, 2 -4, and 3 -5 (Fig. 1) Park and Tulinsky [lo] have published an Xray crystallographic structure, at 0.28-nm resolution, of the bovine prothrombin fragment 1, which contains the protein's first kringle. The picture thus generated indicates a tight, globular structure with the second and third disulfide bridges closely interacting, centrally positioned within the domain.