title: Proline-rich cytokine from neurosecretory granules: a new natural substrate for dipeptidyl peptidase IV.
abstract: A proline-rich cytokine from neurosecretory granules of bovine neurohypophysis, 15 amino acids containing PRP-1 (Ala-Gly-Ala-Pro-Glu-Pro-Ala-Glu-Pro-Ala-Gln-Pro-Gly-Val-Tyr), had been demonstrated as a unique regulator of activity of neurons, strong antibacterial agent, and mediator of the hypothalamus-neurohypophysis-bone marrow-thymus axis, which participates in hematopoietic stem cells differentiation. In the present work it was shown that this neuropeptide represents a new natural substrate for Dipeptidyl Peptidase IV (DPPIV). The time-dependent increase of primary amines quantity in the assay mixture of PRP-1 and DPPIV has been observed allowing to conclude, that DPPIV catalyses the enzymatic reaction of PRP-1 cleavage. The amount of primary amines in the assay mixtures was evaluated using o-phtaldialdehyde dye. The gel-filtration and paper electrophoresis analyses proved this conclusion. The catalytic parameters of catalyzed by DPPIV enzymatic reaction of PRP-1 cleavage were determined as: V(max) = 1.27 ± 0.11 nmol/min and K(m) = 0.38 ± 0.1 mM.
authors.affiliation: H. Buniatyan Institute of Biochemistry of Armenian NAS, 5/1 P. Sevak Str, Yerevan 0014, Republic of Armenia.
authors.forename: Alvard A
authors.initials: AA
authors.lastname: Antonyan
authors.forename: Svetlana G
authors.initials: SG
authors.lastname: Sharoyan
authors.forename: Sona S
authors.initials: SS
authors.lastname: Mardanyan
authors.forename: Armen A
authors.initials: AA
authors.lastname: Galoyan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism*; D018819:Dipeptidyl Peptidase 4 / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D011392:Proline / Q000378:metabolism*; D022142:Secretory Vesicles / Q000737:chemistry*
chemical_list: D016207:Cytokines; D010446:Peptide Fragments; D011392:Proline; D018819:Dipeptidyl Peptidase 4