Pavel Majer

Design of sensitive fluorogenic substrates for human cathepsin D

Cathepsin D is a lysosomal aspartic proteinase that has been implicated in several pathological processes such as breast cancer and Alzheimers disease. We designed and synthesized a number of quenched fluorogenic substrates with P2 variations in the series AcEE(EDANS)KPIXFFRLGK(DABCYL)E‐NH2, where X=cysteine, methylcysteine, ethylcysteine, tert‐butylcysteine, carboxymethylcysteine, methionine, valine or isoleucine. Most of the fluorogenic substrates exhibited greater k cat/K m ratios than the best cathepsin D substrates described so far. Differences in kinetic constants, which were rationalized using structure‐based modeling, might make certain substrates useful for particular applications, such as active site titrations or initial velocity determination using a fluorescent plate reader.

Facile stereoselective synthesis of γ-substituted γ-amino acids from the corresponding α-amino acids

Abstract A facile stereoselective method for the synthesis of γ-substituted, γ-amino acids from α-amino acids was developed. The key step of the procedure is complete reduction of the keto functionality of α-amino acyl Meldrums acid by sodium acetoxyborohydride. The resulting amino alkyl Meldrums acid undergoes thermal decarboxylative ring closure to a 5-substituted pyrrolidinone which yields the corresponding γ-amino acid after basic hydrolysis. The overall yield of the procedure ranges from 40 to 65%.