Erich Hochuli

Lipstatin, a new and very potent inhibitor of pancreatic lipase (the key enzyme of intestinal fat digestion) was isolated from Streptomyces toxytricini. Lipstatin contains a beta-lactone structure that probably accounts for the irreversible lipase inhibition. The IC50 of lipstatin for pancreatic lipase is 0.14 microM. In mice triolein absorption was dose-dependently inhibited by lipstatin, whereas oleic acid was absorbed normally. Other pancreatic enzymes, such as phospholipase A2 and trypsin, were not inhibited even at an inhibitor concentration of 200 microM.

The 6xHis/Ni-NTA system is a fast and versatile tool for the affinity purification of recombinant proteins and antigenic peptides. It is based on the high-affinity binding of six consecutive histidine residues (the 6xHis tag) to immobilized nickel ions, giving a highly selective interaction that allows purification of tagged proteins or protein complexes from <1% to >95% homogeneity in just one step (1, 2). The tight association between the tag and the resin allows contaminants to be easily washed away under stringent conditions, yet the bound proteins can be gently eluted by competition with imidazole, or a slight reduction in pH. Moreover, because the interaction is independent of the tertiary structure of the tag, 6xHis labeled proteins can be purified even under the strongly denaturing conditions required to solubilize inclusion bodies.

The structure of a new pancreatic lipase inhibitor, lipstatin, produced by Streptomyces toxytricini was determined as (2S,3S,5S,7Z,10Z)-5-[(S)-2-formamido-4-methylpentanoyloxy ]-2-hexyl-3- hydroxy-7,10-hexadecadienoic lactone by spectroscopic and chemical methods. Structurally lipstatin is closely related to the known esterase inhibitor esterastin. It contains a N-formyl-L-leucine side chain instead of the N-acetyl-L-asparagine in esterastin.