Abstract

Since the discovery of MACC as a major metabolite of both endogenous and
exogenously applied ACC, it has become evident that the formation of MACC from
ACC can act to regulate ethylene production in certain tissues. Hence, it was
suggested that MACC could serve as an indicator of water-stress history in plant
tissues. The accurate quantification of MACC in plant tissues is essential for the
understanding of the role of MACC in the regulation of ethylene biosynthesis.
Hoffman and co-workers described a method for the measurement of MACC in
which it was hydrolysed by HC1 to ACC, which was then assayed by chemical
oxidation to form ethylene. To date, no other method has been developed for
quantifying MACC. Attempts have been made by others to raise monoclonal
antibodies to MACC so that an irnrnunoassay could be developed in order to gain a
deeper understanding of stress-induced ethylene production. However, to date, no
further publications have been forthcoming. Here, quantification methods for MACC
, employing GC-MS are described. This method is compared with widely-used
indirect assay for MACC, which is based upon hydrolysis of MACC to ACC and
conversion of ACC by hypochlorite reagent to ethylene which is subsequently
quantified by gas chromatography