Hydrolysis of various bioactive peptides by goat brain dipeptidylpeptidase-III homologue.
DPP-III from goat brain was purified to apparent electrophoretic homogeneity which showed several characteristics similar to other reported DPP-IIIs although it possesses dissimilar molecular weight and different inhibition behavior. Thin layer chromatographic studies with goat brain DPP-III revealed that it hydrolyses Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) at the Gly-Gly bond producing Tyr-Gly and Gly-Phe-Leu with no further degradation of liberated tripeptide. (Ala)(4) is hydrolyzed to dialanine whereas trialanine is not cleaved. ACTH, angiotensin II and III were also hydrolyzed whereas angiotensin I was not. It was concluded that the enzyme requires at least a tetrapeptide to act and that it removes a dipeptidyl moiety from the NH(2)-terminus of the studied peptides. Goat brain DPP-III may be involved in the metabolism of very important bioactive peptides such as enkephalins and angiotensins.
Department of Biochemistry, Kurukshetra University, Kurukshetra, Haryana, India. dhandasuman@rediffmail.com
Suman
S
Dhanda
Jasbir
J
Singh
Hari
H
Singh
D000324:Adrenocorticotropic Hormone / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D000803:Angiotensin I / Q000737:chemistry / Q000378:metabolism; D000804:Angiotensin II / Q000737:chemistry / Q000378:metabolism; D000805:Angiotensin III / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002855:Chromatography, Thin Layer; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000737:chemistry / Q000378:metabolism; D006041:Goats / Q000378:metabolism*; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013758:Tetragastrin / Q000737:chemistry / Q000378:metabolism
D010455:Peptides; D013758:Tetragastrin; D000804:Angiotensin II; D000805:Angiotensin III; D004743:Enkephalin, Leucine; D000324:Adrenocorticotropic Hormone; D000803:Angiotensin I; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases