In:
Parasitology, Cambridge University Press (CUP), Vol. 116, No. 6 ( 1998-06), p. 525-532
Abstract:
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 NH 2 -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 [ 35 S] methionine, and only the gut and fat body showed synthesis of BYC polypeptides.
Protein sequencing of both the NH 2 -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.
A role of BYC in degradation of vitellin, the
major yolk protein of tick eggs, is discussed.
Type of Medium:
Online Resource
ISSN:
0031-1820
,
1469-8161
DOI:
10.1017/S0031182098002698
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
1998
detail.hit.zdb_id:
1491287-9
SSG:
12
Bookmarklink