Respiratory infections, including Mycoplasma pneumoniae (Mp), contribute to asthma pathobiology. To date, the mechanisms underlying the increased susceptibility of asthmatics to airway Mp infection remain unclear. Short palate, lung, and nasal epithelium clone 1 (SPLUNC1) protein is a recently described large airway epithelial cell-derived molecule that was predicted to exert host defense activities. However, SPLUNC1 function and regulation in an infectious or allergic milieu are still unknown. We determined host defense and anti-inflammatory functions of SPLUNC1 protein in Mp infection and the regulation of SPLUNC1 by Mp and allergic inflammation (e.g., IL-13). SPLUNC1 function was examined in Mp or human airway epithelial cell cultures by using SPLUNC1 recombinant protein, overexpression and RNA interference. Human and mouse bronchial epithelial SPLUNC1 was examined using immunostaining, Western blotting, ELISA, laser capture microdissection, and real-time PCR. Mouse models of Mp infection and allergic inflammation and air-liquid interface cultures of normal human primary bronchial epithelial cells were used to study SPLUNC1 regulation by Mp and IL-13. We found that: 1) SPLUNC1 protein decreased Mp levels and inhibited epithelial IL-8 production induced by Mp-derived lipoproteins; 2) normal human and mouse large airway epithelial cells expressed high levels of SPLUNC1; and 3) although Mp infection increased SPLUNC1, IL-13 significantly decreased SPLUNC1 expression and Mp clearance. Our results suggest that SPLUNC1 serves as a novel host defense protein against Mp and that an allergic setting markedly reduces SPLUNC1 expression, which may in part contribute to the persistent nature of bacterial infections in allergic airways.

A crude lipase, Newlase F, was used to remove C-terminal protecting groups from dipeptide esters. Hydrolysis of dipeptide n-heptyl esters with Newlase F was conducted in aqueous media containing acetonitrile. The optimum pH and temperature of lipase in Newlase F were 7.0 and 30 ◦C, respectively. Low level acetonitrile promoted the hydrolysis of dipeptide n-heptyl esters, while high level acetonitrile inhibited the hydrolysis. However, the protease activity in Newlase F was significantly inhibited by acetonitrile. Lipase in Newlase F worked better in a medium containing water-miscible organic solvents than in water-immiscible ones. N-terminal protecting groups were not affected by the protease in the crude enzyme. It was found that the protease in Newlase F did not hydrolyze amide bond with hydrophilic amino acids on either side under these conditions (pH 7.0, room temperature). Newlase F may consequently be used widely in the synthesis of peptide conjugates. The crude enzyme was immobilized on SBA-15 mesoporous molecular sieve. The lipase activity of immobilized preparation was more active on hydrolysis of C-terminal protecting groups and stable than the free enzyme. The immobilization also reduced the protease activity.

The biomimic reactions of N phosphoryl amino acids are very important in the study of many biochemical processes, it was found that the α-COOH group, and not the γ-COOH, was involved in the ester exchange on phosphorus experimentally. The reactions, had been proposed to be related to intramolecular penta coordinate phosphoric carboxylic mixed anhydiides. N Dimethylphosphoryl glutamic acid (DMP Glu) was selected as model compound to study the reactivity difference between the α-COOH and γ-COOH group. From MNDO calculations, the energy of the penta coordinate phosphoric intermediates contain ing five membered ring from a COOH was 40.8 ld/mol lower than that of the seven membered one from γ-COOH. This resnlt was in agreement with those from HF/6-31G** and B3LYP/6 31G** calculations. Theoretical tln-ee dimensional potential energy snrface of frothing the intermdiates predicted that the transition states 4 and 5 involving α-COOH or γ-COOH gronp had energy baniers of △E=196.1 and 216.9 kJ/mol, respectively. So the α-COOH conld be differentiated from γ-COOH intramolecnlarly in glutantic acid by N phosphorylation.