Inhibition of proline endopeptidase activity by acyl-coenzyme A esters.
Coenzyme A (CoA), its related compounds and acylcarnitine non-competitively inhibited the activity of proline endopeptidase (PEPase) purified from rat liver cytosol. The degree of inhibition was in the order of acyl-CoA greater than CoA greater than dephospho-CoA greater than or equal to acylcarnitine. However, carnitine did not inhibit the enzyme activity. Among the compounds examined, n-decanoyl-CoA showed the highest inhibitory activity (Ki = 9 microM). These results suggest that both the acyl group and CoA contribute to the inhibition of PEPase by acyl-CoA. The abilities of n-decanoyl-CoA and its related compounds to quench the intrinsic fluorescence at 332 nm from PEPase excited at 280 nm, was used as a probe for the binding affinity of the enzyme for these compounds. The quenching of fluorescence by CoA was nearly equal to that by n-decanoyl-CoA. n-Decanoylcarnitine and carnitine were unable to quench the fluorescence. These results indicate that n-decanoyl-CoA at least binds to PEPase through its CoA portion.
Yamakawa
N
N
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Fukuoka University, Japan.
Shimeno
H
H
Soeda
S
S
Nagamatsu
A
A
D000214:Acyl Coenzyme A / Q000494:pharmacology*; D000818:Animals; D002264:Carboxylic Acids / Q000494:pharmacology*; D002331:Carnitine / Q000494:pharmacology; D003065:Coenzyme A / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D010450:Endopeptidases / Q000378:metabolism*; D004952:Esters / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D000085822:Prolyl Oligopeptidases; D051381:Rats; D012697:Serine Endopeptidases; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship
D000214:Acyl Coenzyme A; D002264:Carboxylic Acids; D004952:Esters; C045561:decanoyl-coenzyme A; D010450:Endopeptidases; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases; D002331:Carnitine; D003065:Coenzyme A