Characterization of trypsin-modified bovine lens acylpeptide hydrolase.
Acylpeptide hydrolase, which removes the N-acetylated amino acids from peptide substrates was purified from bovine lens, truncated in vitro to a 55 kDa enzyme by trypsin digestion and characterized. The activity of the trypsin-modified enzyme was investigated using alpha A-crystallin and oxidized insulin A chain. The trypsin-modified enzyme was able to unblock alpha A-crystallin and displayed endoprotease activity unlike the native enzyme. SDS-PAGE analysis and amino acid sequencing of (3H)iPr2P-F labeled bovine lens acylpeptide hydrolase showed that the lens has a 55 kDa truncated form of the enzyme. The in vivo truncated form of the enzyme was generated by the cleavage of the Gly203-Asp204 peptide bond in the native enzyme.
Chongcharoen
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Mason Eye Institute, Department of Ophthalmology, University of Missouri, Columbia 65212, USA.
Sharma
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D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D006868:Hydrolysis; D007328:Insulin / Q000378:metabolism; D007908:Lens, Crystalline / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D014357:Trypsin
D007328:Insulin; D010447:Peptide Hydrolases; C038220:acylaminoacyl-peptidase; D014357:Trypsin