Unveiling a novel serpinB2-tripeptidyl peptidase II signaling axis during senescence.

Tripeptidyl peptidase II (TPPII or TPP2) degrades N-terminal tripeptides from proteins and peptides. Studies in both humans and mice have shown that TPPII deficiency is linked to cellular immune-senescence, lifespan regulation and the aging process. However, the mechanism of how TPPII participates in these processes is less clear.

Development of Activity-Based Probes for Imaging Human α-l-Fucosidases in Cells.

We have established a concise synthetic route relying on a key base-promoted epimerization step to synthesize two series of activity-based probes carrying a BODIPY fluorophore for α-l-fucosidase. The resulting probes were evaluated for labeling performance. The one utilizing an o-fluoromethylphenol derivative as the latent trapping unit was successfully applied for the first time to visualize and locate lysosomal α-l-fucosidase activity in human cells.

Fluorous oxime palladacycle: a precatalyst for carbon-carbon coupling reactions in aqueous and organic medium.

To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for a wide range of carbon-carbon bond formation reactions (Suzuki-Miyaura, Sonogashira, Stille, Heck, Glaser-type, and Kumada) in either aqueous or organic medium under microwave irradiation. Palladacycle 1 could be recovered through F-SPE in various coupling reactions with recovery ranging from 84 to 95% for the first cycle. Inductively coupled plasma optical emission spectrometry (ICP-OES) analyses of the Pd content in the crude product from each class of transformation indicated extremely low levels of leaching and the palladacycle could be reused four to five times without significant loss of activity.

Utilizing hydrolases of opposite enantiopreference for the preparation of both enantiomers of (1R,7aR)-(-)- and (1S,7aS)-(+)-3,6,7,7a-tetrahydro-1-hydroxy-7a-methyl-1H-inden-5(2H)-one.

Four racemic esters of (1R*,7aR*)-3,6,7,7a-tetrahydro-1-hydroxy-7a-methyl-1H-inden-5(2H)-one were prepared and subjected to hydrolysis with two types of hydrolases, including alcalase and three lipases. Alcalase and lipase showed opposite enantiopreference on these esters. Based on this result, we developed a gram-scale procedure using butanoate as the substrate, which was treated consecutively with alcalase and lipase from Candida rugosa (CRL), to give both enantiomers of the title compound in high yields and high enantiomeric excess.

A convenient chemoenzymatic synthesis of (4aS,5S)-(+)-4,4a,5,6,7,8-hexahydro-5-hydroxy-4a-methylnaphthalen-2(3H)-one.

We have developed a convenient chemoenzymatic method for the preparation of (4aS,5S)-4,4a,5,6,7,8-hexahydro-5-hydroxy-4a-methylnaphthalen-2(3H)-one by taking advantage of the excellent enantioselectivity of alcalase. Four different esters were compared, and the butanoate ester was found to be the best substrate. The stereochemistry of the product is the same as the one predicted from the binding model of alcalase.