The pancreatic Kunitz inhibitor, also known as aprotinin, bovine basic pancreatic trypsin inhibitor (BPTI), and trypsin-kallikrein inhibitor, is one of the most extensively studied globular proteins. It has proved to be a particularly attractive and powerful tool for studying protein conformation as well as molecular bases of protein/protein interaction(s) and (macro)molecular recognition. BPTI has a relatively broad specificity, inhibiting trypsin- as well as chymotrypsin- and elastase-like serine (pro)enzymes endowed with very different primary specificity. BPTI reacts rapidly with serine proteases to form stable complexes, but the enzyme: inhibitor complex formation may involve several intermediates corresponding to discrete reaction steps. Moreover, BPTI inhibits the nitric oxide synthase type-I and -II action and impairs K+ transport by Ca2+-activated K+ channels. Clinically, the use of BPTI in selected surgical interventions, such as cardiopulmonary surgery and orthotopic liver transplantation, is advised, as it significantly reduces hemorrhagic complications and thus blood-transfusion requirements. Here, the structural, inhibition, and bio-medical aspects of BPTI are reported.

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It can be concluded that nanostructured lipid carriers encapsulation may represent an effective strategy to prolong the half-life of bromocriptine.

This article describes the production and characterization of monoglyceride-based supramolecular systems by a simple processing technique, avoiding time-consuming procedures, high energy input, and the use of organic solvents. A preformulatory study was performed to study the influence of the experimental parameters on the production of monoglyceride-based disperse systems. In particular the effects of (1) stirring speed, (2) type and concentration of monoglyceride mixture, and (3) type and concentration of surfactant were investigated on the recovery, fraction of larger particles, mean diameter, and shape of smaller particles (so called nanosomes). Dispersions were first characterized by optical microscopy and freeze-fracture electron microscopy. The mean diameter of standard nanosomes, analyzed by photon correlation spectroscopy (PCS) after elimination of larger particles by filtration, was 193.5 nm. Cryotransmission electron microscopy studies, conducted in order to investigate the structure of dispersions, showed the coexistence of vesicles and particles characterized by a cubic organization. X-ray diffraction data revealed the coexistence of 2 different cubic phases, the first being a bicontinuous cubic phase of spatial symmetry Im3m (Q229) and the second belonging to the Pn3m spatial symmetry. A study on the stability of monoglyceride-based dispersions based on macroscopical analysis of organoleptic properties and dimensional analysis by time was performed after elimination of larger particles by filtration. Organoleptic and morphological features do not change by time, appearing free from phase-separation phenomena for almost 1 year from production. PCS studies showed that nanosomes undergo an initial increase in mean diameter within the first month following production; afterwards they generally maintain their dimensions for the next 4 months.

Human serum albumin (HSA), the most prominent protein in plasma, is best known for its exceptional capacity to bind ligands (e.g. heme and drugs). Here, binding of the anti‐HIV drugs abacavir, atazanavir, didanosine, efavirenz, emtricitabine, lamivudine, nelfinavir, nevirapine, ritonavir, saquinavir, stavudine, and zidovudine to HSA and ferric heme–HSA is reported. Ferric heme binding to HSA in the absence and presence of anti‐HIV drugs was also investigated. The association equilibrium constant and second‐order rate constant for the binding of anti‐HIV drugs to Sudlow's site I of ferric heme–HSA are lower by one order of magnitude than those for the binding of anti‐HIV drugs to HSA. Accordingly, the association equilibrium constant and the second‐order rate constant for heme binding to HSA are decreased by one order of magnitude in the presence of anti‐HIV drugs. In contrast, the first‐order rate constant for ligand dissociation from HSA is insensitive to anti‐HIV drugs and ferric heme. These findings represent clear‐cut evidence for the allosteric inhibition of anti‐HIV drug binding to HSA by the heme. In turn, anti‐HIV drugs allosterically impair heme binding to HSA. Therefore, Sudlow's site I and the heme cleft must be functionally linked.