Studies on the Extended Active Site of Papain
نویسندگان
چکیده
منابع مشابه
Fluorescence energy transfer studies on the active site of papain.
Measurements have been performed of the excited-state lifetimes and fluorescence yields of papain tryptophan units when acyl derivatives of Phe-glycinal are bound at the active site of the enzyme. The enhancement of tryptophan fluorescence in complexes of papain with the acetyl or benzyloxycarbonyl derivatives is not stereospecific with respect to the configuration of the phenylalanyl residue, ...
متن کاملEvidence for histidine in the active site of papain.
Papain was irreversibly inhibited by 1,3-dibromoacetone, a reagent designed to react first with the active-site cysteine residue and subsequently with a second nucleophile. The molecular weight of the inhibited enzyme was indistinguishable from that of papain itself, and no evidence of dimeric or oligomeric species was found. The optical-rotatory-dispersion curves of chloroacetone-inhibited pap...
متن کاملInvestigation of the active site of papain with fluorescent probes.
7-Chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD chloride) and 7-(2'-hydroxyethylthio)-NBD (obtained from NBD chloride and mercaptoethanol) undergo a reversible spectral change in alkaline solution that depends respectively on a single apparent pK(a) 9.76 (at 25 degrees C) and 8.81 (at 32 degrees C). In acid solution however no spectral change was observed. NBD chloride reacts slowly with papain at...
متن کاملStudies on the active--SH group of papain and on the mechanism of papain activation by thiols.
It is now generally agreed that papain possesses a single reactive sulfhydryl group which is essential for activity and which probably participates in the catalytic mechanism by forming acyl intermediates with the different substrates (2, 3). Smith (4) has claimed that the essential sulfhydryl group of papain is kinetically more active than most protein sulfhydryl groups and that it possesses d...
متن کاملStudies on the Active Site of Clostripain
Clostripain is rapidly and selectively inactivated by the chloromethyl ketone derived from cr-N-tosyl-L-lysine (TLCK) with an apparent second order rate constant of 8.7 X lo4 M-I set-i at pH 6.5. Alkylation by TLCK occurs only with catalytically active enzyme, the rate of which is considerably retarded by the competitive inhibitors, oc-Ntosyl-L-homoarginine methyl ester and benzamidine. In cont...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1974
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)42123-6