Open Accessl ‐Phenylalanine ammonia‐lyase from Phaseolus vulgaris
Author(s) -
BOLWELL G. Paul,
BELL John N.,
CRAMER Carole L.,
SCHUCH Wolfgang,
LAMB Chris J.,
DIXON Richard A.
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb08941.x
Subject(s) - phenylalanine ammonia lyase , polyacrylamide gel electrophoresis , biochemistry , phenylalanine , antiserum , phaseolus , gel electrophoresis , chemistry , elicitor , chromatography , biology , microbiology and biotechnology , enzyme , amino acid , antigen , botany , genetics
1 l ‐Phenylalanine ammonia‐lyase (EC 4.3.1.5) has been purified over 200‐fold from cell cultures of bean ( Phaseolus vulgaris L.) exposed to elicitor heat‐released from the cell walls of the phytopathogenic fungus Colletotrichum lindemuthianum . Four forms of the enzyme, with identical M r but differing apparent pI values of 5.4, 5.2, 5.05 and 4.85, were observed following the final chromatofocussing stage of the purification. 2 A preparation (purified 43‐fold by ammonium sulphate precipitation, gel‐filtration and ion‐exchange chromatography) containing all four forms exhibited apparent negative rate cooperativity with respect to substrates. However, the individual forms displayed normal Michaelis‐Menten kinetics, with K m values of 0.077 mM, 0.122 mM, 0.256 mM and 0.302 mM in order of decreasing apparent pI value. 3 A preparation purified 200‐fold and containing all four forms was used to immunise rabbits for the production of anti‐(phenylalanine ammonia‐lyase) serum. The antiserum was characterised by: (a) immunotitration experiments; (b) solid phase enzyme‐linked immunosorbent assays; (c) comparison of immunoprecipitates of 35 S‐labelled phenylalanine ammonia‐lyase subunits (synthesized both in vivo and in vitro ) on both one‐dimensional and two‐dimensional polyacrylamide gels after immunoprecipitation with the bean antiserum or antisera raised against pea and parsley phenylalanine ammonia‐lyase preparations and (d) immune blotting. 4 Experiments involving (a) immunoprecipitation followed by analysis on SDS/polyacrylamide gels and (b) SDS/polyacrylamide gel electrophoresis followed by immune blotting, indicated that the M r of newly synthesized ( in vivo and in vitro ) bean phenylalanine ammonia‐lyase subunits is 77000; a 70000‐ M r form is readily generated as a partial degradation product during purification. 5 Immunoprecipitates of bean phenylalanine ammonia‐lyase synthesized both in vivo and in vitro showed the presence of multiple subunit types of identical M r but differing in pI. Furthermore, treatment of bean cultures with Colletotrichum elicitor resulted in a 10‐fold increase in phenylalanine ammonia‐lyase extractable activity within 8 h, and chromatofocussing analysis indicated that this was associated with differential increased appearance of the high‐pI, low‐ K m forms as compared to the two higher K m forms. This differential induction was further confirmed by immune blotting of crude extracts subjected to isoelectric focussing.