Renin inhibits N-acetyl-D-glucosamine 2-epimerase (renin-binding protein).
Renin-binding protein (RnBP) is a highly specific renin inhibitor first isolated from porcine kidney. Our recent studies demonstrated that the human RnBP is the enzyme N-acetyl-D-glucosamine (GlcNAc) 2-epimerase [Takahashi, S. et al. (1999) J. Biochem. 125, 348-353]. We have developed a new assay method for GlcNAc 2-epimerase activity using a system of N-acyl-D-hexosamine oxidase coupled with peroxidase and employed this method to study the effects of renin on GlcNAc 2-epimerase activity. The recombinant human (rh) RnBP existed as a dimer and its GlcNAc 2-epimerase activity was strongly inhibited by the purified renin concomitant with the formation of RnBP-renin heterodimer, so-called high molecular weight (HMW) renin. The renin activity was also inhibited by rhRnBP in a dose-dependent manner. These results indicate that renin is an inhibitor of GlcNAc 2-epimerase, and the renin-RnBP heterodimer HMW renin is an inactive form of both renin and GlcNAc 2-epimerase activities.
Takahashi
S
S
Department of Bioengineering, Akita Research Institute of Food and Brewing, Sanuki, Arayamachi, Akita 010-1623, Japan. saori@arif.pref.akita.jp
Kumagai
M
M
Shindo
S
S
Saito
K
K
Kawamura
Y
Y
D002238:Carbohydrate Epimerases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D012083:Renin / Q000502:physiology*; D013379:Substrate Specificity
D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D012083:Renin; D002238:Carbohydrate Epimerases; C024519:N-acyl-D-glucosamine 2-epimerase; C498259:RENBP protein, human