Brain endo-oligopeptidase B: inactivation of LH-RH by hydrolysis of the Pro9-Gly-NH2(10) peptide bond.
1. The site of hydrolysis of rabbit brain endo-oligopeptidase B acting on luteinizing hormone-releasing hormone (LH-RH) was determined by isolating the products by chromatography on Aminex A-5 resin developed with pyridine-acetic acid buffer. The products [des-Gly-NH2(10)]-LH-RH, glycinamide and unhydrolyzed LH-RH were identified and shown to be homogeneous by amino acid analysis and high-voltage paper electrophoresis at pH 2.1 and 3.5 and recovered in yields of 58, 65 and 23%, respectively. 2. A sensitive analytical method for the measurement of 4-40 nmoles of glycinamide with an automatic amino acid analyzer was described. Aminex A-5 resin (0.90 x 15 cm) was eluted with sodium citrate buffer, pH 3.25 (0.2 N Na+) at 32 degrees C and ninhydrin was used for detection. 3. The data show that endo-oligopeptidase B acts as a post-proline cleaving enzyme that inactivates LH-RH by hydrolysis of the Pro9-Gly-NH2(10) peptide bond. The enzyme may participate in the metabolism of LH-RH in the central nervous system.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002845:Chromatography; D003546:Cysteine Endopeptidases; D004590:Electrophoresis, Paper; D010450:Endopeptidases / Q000378:metabolism*; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006868:Hydrolysis; D011394:Proline Oxidase / Q000096:biosynthesis; D011817:Rabbits
D007987:Gonadotropin-Releasing Hormone; C018556:glycine amide; D011394:Proline Oxidase; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; C028307:endopeptidase B; D005998:Glycine