ISSN:
1432-2048
Keywords:
Chloroplast
;
Cytosol
;
Spinacia
;
Thiamin pyrophosphate
;
Transketolase
;
Triticum (transketolase)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Transketolase (E.C. 2.2.1.1.) has been partially purified from wheat (Triticum aestivum, cv. Sappo) and spinach (Spinacia oleracea) leaves. The fully-active enzyme is a tetramer of relative molecular mass (Mr) of 150 kMr requiring thiamin pyrophosphate for maximal activity, and dissociating into a 74 kMr dimer in its absence or in dilute solution. The chloroplastic transketolase (over 75% of the cellular total) is magnesium-stimulated but the cytosolic form is magnesium-insensitive. Both chloroplastic and cytosolic transketolase showed similar broad specificities towards several ketose phosphate substrates including fructose 6-phosphate and sedoheptulose 7-phosphate. Wheat and spinach leaf transketolases are not light-activated and closely resemble the yeast enzyme in many of their properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00429458
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