To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
An aspartic proteinase precursor, herein named BYC
(Boophilus Yolk pro-Cathepsin) was isolated from eggs of the hard
tick, Boophilus microplus. As judged by electrophoresis on sodium
dodecyl sulfate polyacrylamide slab gel (SDS–PAGE),
purified BYC presented 2 bands of 54 and 49 kDa, bearing the same
NH2-terminal amino acid sequence. By Western blot
analysis, BYC was also found in the haemolymph, indicating an extraovarian
site of synthesis. Several organs were incubated in culture medium with
[35S] methionine, and only the gut and fat body
showed synthesis of BYC polypeptides.
Protein sequencing of both the NH2-terminal and an internal
sequence obtained after cyanogen bromide (CNBr) cleavage
of BYC revealed homology with several aspartic proteinase precursors.
Incubation at pH 3·5 resulted in autoproteolysis of
BYC, which produced the mature form of the enzyme, that displayed
pepstatin-sensitive hydrolytic activity against
haemoglobin. Western blot analysis using anti-BYC monoclonal antibodies
showed proteolytic processing of BYC during
embryogenesis and suggested activation of the enzyme during development.
role of BYC in degradation of vitellin, the
major yolk protein of tick eggs, is discussed.
Email your librarian or administrator to recommend adding this to your organisation's collection.