Metabolic stability of human parathyroid hormone peptide hPTH (1-34) in rat tissue homogenates: kinetics and products of proteolytic degradation.
The present study aim to investigate the metabolic stability and degradation of cleavage sites of human parathyroid hormone peptide, hPTH (1-34), in rat tissue homogenate, and to identify the types of proteases involved in hPTH (1-34) processing degradation. The stability of hPTH (1-34) in rat kidney, lung and liver homogenates was evaluated by LC-ESI-MS, and the structures of the major degradation products were identified by MALDI-TOF MS and LC-ESI-MS/MS. The ability of protease inhibitors to inhibit hPTH (1-34) degradation was used to identify the class of proteases involved in the metabolism of hPTH (1-34). hPTH (1-34) peptide was readily degraded in rat kidney, liver, and lung homogenates, with half-lives of 5.7, 32.2, and 18.9 min, respectively. The degradation of hPTH (1-34) in each tissue can be inhibited by inhibitors of serine and metalloproteases. The major degradation products of hPTH (1-34) are similar in each tissue and suggest that hPTH (1-15) and hPTH (16-34) appear as the major degradation products. The degradation patterns of hPTH (1-34) incubated in rat kidney, liver and lung homogenates are largely overlapping, and a majority of the fragments are generated via cleavages at sites of Leu15-Asn16 peptide bond.
Liao
Sha
S
Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Haidian District, 100850, Beijing, People's Republic of China.
Qie
Jian-Kun
JK
Xue
Ming
M
Zhang
Zhen-Qing
ZQ
Liu
Ke-Liang
KL
Ruan
Jin-Xiu
JX
D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D010281:Parathyroid Hormone / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D010281:Parathyroid Hormone