Vol. 16—1962 - NorthEastern Weed Science Society

'. '.32
. dialysis against 'both EDTAand vater. Therefore, ,'wnatever is 'be1ngCh~Fed
,_"is a macromolecule. The precip;ttate itself is 11Iorethan 90%protein but
'does contain SOiftenucleic acid)~ ,sbinepetrtin' tyjle subs.tances and airlaU qUtq1­
'tities of lipid. While we have found that' the .~&fi"tilm of cOmmercial ~~'to%'Us
pectin will, in fact, alter the heat coaSU1abU1~"of pea proteins, tho;
.quanti ties which we have hatt to add to produce this >I'lffeot are so large as
.to be physio16g1cally unimportant in our, e:xperimen~~ ,The. crucial'test, .
of the hypothesis that: pectins 8rtil altering the h~~~ coagulability of ,', .
.proteins would be to isolate the pectins from pee.s~ add them to the proteins
-and exaininethe effect 9fphy'aiological quantitie'is~fth\>se matwrials 01,1 "
the 'heat coagulabilitY' patterns. We are currentl;r. pvrforming such exPeriment.s,
.. . ! .
Wehave also found that the auxin-induced reaction can be inhiBited
,very markedly bY'ethionine at about 10-.3 M.Ano~Elr !ntp.bitor which SQElzaS
to work fairly well is p-fluorOphenye.lanine.Siijde'bcith these substanclilS'
are amino acid antagonists (for tyrosine and methionine rospectively)' We '.
,.,.infer thllt protein synthesis '~ be involved 1ntJ11s auxin-induced roa~ori.
This is a h!ghl$ tentative conclusion which must. ~·'axami.ned further, :.
especially in view of the factthe.t ethionine is aleo'a competitor with .
methionine for methyl group transfer reactions WhiChmayinvolve the pectins.
Other' genara~inhibitors which have been found ett.octiive aro 2-4-dinit1'qphonol,
at about l~ molar, iodoacetic acid at about 10-4 1I!0.larand potassiQlllC1!lnide
at about 10-3 molar. The reactionalilo fails to occur in an atmosphere' :
devoid of oxygen."
Wehave als~ attompted to obtain evidence for .or against the fo;rmation.
of a of anew pr?tein under tha:1pfluonqaof auxin \:)ysubjecting the par,tia1ly
purifiGd soluble supernatant protein to ,electp:ph~sis both on paper and
on starch. Our resUlts to date show that apprClXi!1l8telyfour maj"or peaks.
are present in the electrophoretic patterns ot the: prqtei,tls, at pH 8.6 .. '
with verona'l, ·buffer. .These se6ll1to be. altered qu~ti~atively as a res)1lt
of auxin application, and one new small peak arises as the resUlt of8UXin
application. The interpretation Qt:these :r:esu.J.ts1s ~ome'Hh£'.tuncertain, .
and must nwai-tf'urther work•. Ou,r ,.tentati've concl~on is, however, that ,
auxin treatmont has somehowalterod the protein :spe'ctrum of the cell, ,OM
that such alteration may lead to somo or all ot thegt'owth effects noted'
as a r"sul t of auxin applicotion. . :' . . .
References
A) Some of the data for the conclusions cited above aro"£ound in:
1) Galston. A.W, and Kaur, R. An effect of a\ixins on th0 heat
coagulability of the proteins of growing plant cells. Proc.
Natl. Acad. Sci, (U.S.). l!2,,1587-1590, 195~. '
2) and • The intracollular locale of auxin actiam'
Ane1'l'ect of auxin onthe physical state.~f cytopltsmic proteins.
in. Plant Growth Regulation, Proceedihgs of: the IVth Inti.· Conf'er-J
enoa. 355-362. Iowa State College Press, 'Ames, Iowa. 1961.