Qu-Ming Gu

A facile enzymatic resolution process for the preparation of (+)-S-2-(6-hethoxy-2-naphthyl)propionic acid (Naproxen).

Abstract (+)- S -2-(6-Methoxy-2-naphthyl)propionic acid ( 1 ) has been prepared via enzymatic enantlospecific hydrolysis of(±)-chloroethyl-2-(6-methoxy-2-naphthyl) propionate ( 3 ), catalyzed by the lipase of Candida cylindracea.

Improving the Enantioselectivity of the Candida Cylindracea Lipase Via Chemical Modification

The lipase of Candida cylindracea (B-form) was treated with the classical chemoselective reagents with a view to modifying the specific amino acid residue(s) in the protein. Nitration of the tyrosyl residues of this enzyme was achieved using an excess of tetranitromethane (TNM). This chemically modified TNM-lipase showed a remarkable improvement in enantioselectivity towards the hydrolysis of a series of aryloxypropionic and arylpropionic esters.

Synthesis and characterization of cyclic ATP-ribose: a potent mediator of calcium release

Abstract Cyclic ATP-ribose, synthesized by a combination of chemical and enzymatic methods, was twenty times more potent than cADPR in inducing Ca 2+ release from rat brain microsomes. It induced Ca 2+ release from the same Ca 2+ stores as that of cADPR, but different from those of IP 3 and cyclic ADP-ribose-phosphate.

Bifunctional chiral synthons via biochemical methods. VIII. Optically-active 3-aroylthio-2-methylpropionic acids.

Abstract Optically-active 3-aroylthio-2-methylpropionic acids have been prepared via lipase-catalyzed enantiospecific hydrolysis of their corresponding esters.

Enzymatic preparation of (3S,6R) and (3R,6S)-3-hydroxy-6-acetoxycyclohex-1-ene

Pseudomonas cepacia lipase-catalyzed enantioselective hydrolysis of 2 in water afforded (3S,6R)-3. The antipode (3R,6S)-3 was prepared by enantioselective acylation of 4 using the same enzyme.

ENZYMATIC CYCLIZATION OF NICOTINAMIDE ADENINE DINUCLEOTIDE PHOSPHATE (NADP)

Abstract The ADP-ribosyl cyclase of Aplysia californica catalyzed the conversion of NADP, 3′-NADP and 2′,3′-cyclic NADP into their corresponding cyclic nucleotides (established by NMR, UV, and MS analyses). Cyclic-ADP-ribose-phosphate (cADPRP) was more potent than cADPR in mobilizing calcium in the rat brain microsomal system; the EC50 for cADPRP and cADPR were 9.2 μM and 22 μM respectively.

Bioorganic chemistry of cyclic ADP-ribose (cADPR)1In memory of Sir Derek H. R. Barton, 1918–1998.1

The objective of this brief review is to present an overview of the bioorganic chemistry of cyclic-ADP-ribose (cADPR) with special emphasis on the methodology used for the synthesis of analogues of cADPR. New structural analogues of cADPR can be prepared using either the biomimetic method or ADP-ribosyl cyclase from Aplysia californica. For the most part, both procedures give similar product profiles, but higher yields are generally obtained with the enzymatic method. These synthetic methodologies have allowed the transformation of a variety of structurally modified analogues of NAD+ into their corresponding cyclic nucleotides. Several of these novel analogues are more potent than cADPR in inducing calcium release and are also more stable towards degradative enzymes. They could serve as valuable affinity probes for the isolation of cADPR-binding proteins.

5(4H)-Oxazolinones as acyl donors in papain-catalyzed peptide fragment condensations

Abstract Papain, a thiol protease was shown to utilize 5(4H)-oxazolinones of peptides as acyl donors in peptide segment condensations. The effectiveness of this methodology is illustrated by the successful coupling of oxidized insulin B chain (30 residues) to angiotensin III (7 residues) in 59% yield.