Title: Comparative biochemistry of penguin egg- white proteins—I. ovomucoids: Composition and inhibitory activities for trypsin, α-chymotrypsin and subtilisin
Abstract: 1. The physical, chemical and inhibitory properties of ovomucoids from six species of penguins were compared with one another and with certain properties of other proteinase inhibitors. The six ovomucoids had very similar compositions, physical properties and capacities to inhibit different proteolytic enzymes. 2. Many of the inhibitors were capable of inhibiting bovine trypsin, bovine α-chymotrypsin or subtilisin. The sites for inhibiting trypsin were independent from the sites for inhibiting α-chymotrypsin or subtilisin, while the sites for these latter two enzymes were similar or overlapping. 3. The ovomucoids of the penguins were the only inhibitors which strongly inhibited subtilisin and weakly inhibited α-chymotrypsin. With casein as a substrate, the approximate Kdiss of the EI complexes of penguin ovomucoid with subtitilisin, trypsin and α-chymotrypsin were 1·5 × 10−9 M, 8 × 10−8 M and 3 × 10−6 M, respectively. With benzoyl-l-tyrosine ethyl ester as substrate, subtilisin quantitatively displaced α-chymotrypsin from penguin ovomucoid. 4. Incubation of either subtilisin or α-chymotrypsin with penguin or turkey ovomucoid in acidic solutions appeared to hydrolyze the peptide bonds of similar sequences of leucine-glycine, indicating similar binding sites on the two ovomucoids for the two enzymes.
Publication Year: 1974
Publication Date: 1974-08-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 8
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot