Methionine metabolism, leading to the biosynthesis of ethylene in Saccharomyces cerevisiae does not appear to involve S-adenosylmethionine (SAM) and aminocyclopropanecarboxylic acid (ACC), based on the lack of ethylene synthesis when both SAM and ACC were incubated in the presence and absence of cells. Thus, the mechanism leading to the formation...
To begin the development of a research tool for use in the in
vivo study of S-adenosylmethionine (SAM) metabolism, I attempted
to locate, isolate, clone and elicit the expression of the SAM
hydrolase gene (E.C. 3.3.1.2) of the coliphage T3.
The gene was isolated and cloned into the M13mp8 cloning...
Methylthioadenosine (MTA) is a naturally occuring nucleoside formed during
the synthesis of polyamines in mammalian cells. MTA is rapidly catabolised
by MTA phosphorylase (MTAase), eventually yielding methionine and
adenine. MTAase has been shown to be active in all normal cells, but
deficient in some cells and tissues of malignant origin....
5'-Deoxy-5'-methylthioadenosine phosphorylase catalyzes
the phosphorolytic cleavage of 5'-deoxy-5'-methylthioadenosine
to form 5'-deoxy-5'-methylthioribose-1-phosphate and
adenine in mammalian cells and plays an important role in
methionine and purine salvage. The enzyme is abundant in
normal tissues and in cell lines derived from normal cells.
However, several malignant tissues and cell lines have been...
Rhizobium, in symbiotic association with leguminous plants, is able to fix atmospheric nitrogen after first forming root nodules. Since polyamines are associated with and found in high concentration in rapidly growing cells and are thought to be important for optimal cell growth, it is possible that these polycations are involved...
This research has focussed upon both the in vitro and in vivo characterization
of the recycling pathway leading from 5'-deoxy-5'-methylthioadenosine
to methionine in fruit. In addition to contributing towards polyamine
biosynthesis and other important cellular functions, in plant tissues
these events also serve to generate the hormone ethylene. A broad...
Although the biological occurrence of 5'-methylthioadenosine
(MTA) and 5-methylthioribose (MTR) were recognized more than a half
century ago, very little light has been cast on the physiologic significance
of either substance. My studies were designed to extend
our knowledge of the metabolism of MTA and to determine if this pathway...