ON THE MECHANISM OF INDOLEACETIC ACID OXIDATION BY WHEAT LEAF ENZYMES

1956 ◽  
Vol 34 (1) ◽  
pp. 54-59 ◽  
Author(s):  
E. R. Waygood ◽  
Ann Oaks ◽  
G. A. Maclachlan
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Induction Period ◽  
Indoleacetic Acid ◽  
Acid Oxidation ◽  
Not Given ◽  
Carbon Dioxide Evolution ◽  
Enzyme Preparations ◽  
Wheat Leaf ◽  
Wheat Leaves

Partially purified enzyme preparations of wheat leaves oxidize indoleacetic acid completely in the presence of manganese and a monohydroxyphenol or resorcinol. A characteristic feature of the oxygen uptake is an induction period followed by a rapid oxygen uptake which ceases when 1 mole of oxygen is consumed per mole indoleacetic acid added. One mole of carbon dioxide is evolved per mole indoleacetic acid. There is no lag in carbon dioxide evolution, but it is not given off anaerobically. Oxygen, blue light, and acetaldehyde overcome the induction period. Hydrogen peroxide formed in a final aerobic dehydrogenase step is utilized to provide a source of manganic ions which act as an electron acceptor in an initial oxidative step.

THE ENZYMICALLY CATALYZED OXIDATION OF INDOLEACETIC ACID

1956 ◽  
Vol 34 (6) ◽  
pp. 905-926 ◽  
Author(s):  
E. R. Waygood ◽  
Ann Oaks ◽  
G. A. Maclachlan
Keyword(s):  
Indoleacetic Acid ◽  
Maleic Hydrazide ◽  
Organic Peroxide ◽  
Horse Radish Peroxidase ◽  
Reaction Sequence ◽  
Leaf Extracts ◽  
Naturally Occurring ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Catalyzed Oxidation

Dialyzed wheat leaf extracts, catalase, and horse-radish peroxidase catalyze the decarboxylation and oxidation of indoleacetic acid at pH 5.0–6.0 in the presence of critical concentrations of manganese and monohydric phenols or resorcinol. The equivalent of 1 mole of carbon dioxide is liberated and 1 mole of oxygen consumed per mole of substrate. Manganic ions formed by a phenol–peroxidase–peroxide system initiate the decarboxylation and oxidation. A naturally occurring ether soluble factor from wheat leaves, and maleic hydrazide, can substitute for the active phenols. Catechol, hydroquinone, pyrogallol, seopoletin, and riboflavin, etc. competitively inhibit the oxidation. The nature of the active peroxide is discussed and a reaction sequence involving an organic peroxide or radical rather than hydrogen peroxide is submitted as being a possibility.

STUDIES IN THE MODE OF ACTION OF ROYAL JELLY IN HONEYBEE DEVELOPMENT: II. RESPIRATION OF NEWLY EMERGED LARVAE ON VARIOUS SUBSTRATES

1959 ◽  
Vol 37 (5) ◽  
pp. 803-813 ◽  
Author(s):  
R. W. Shuel ◽  
S. E. Dixon
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Mode Of Action ◽  
Royal Jelly ◽  
Water Soluble ◽  
Older Worker ◽  
Carbon Dioxide Evolution ◽  
Carbon Dioxide Output ◽  
Nutritional Balance

Measurements were made of oxygen uptake and carbon dioxide evolution, during the first 24 hours of life, by larvae on substrates of different age and type. These substrates included royal jelly, the pharyngeal secretion fed to larvae destined to become queens, which varied in age from 0 to 96 hours; the pharyngeal secretion fed to young larvae destined to be workers, which varied in age from 0 to 60 hours and which was termed "worker jelly"; and the food supplied to older worker larvae, composed of a pharyngeal secretion modified by an admixture of honey and pollen, and termed "modified jelly". The pattern and magnitude of oxygen uptake was similar on all substrates. Net carbon dioxide evolution by larvae on royal jelly or modified jelly was highly positive; net carbon dioxide evolution by larvae on worker jelly was slightly negative. Microchemical analyses showed that royal jelly differed in composition from worker jelly and modified jelly. The composition of royal jelly remained relatively constant with age. The addition of sugars to worker jelly produced an increase in carbon dioxide output which was nullified by the further addition of an extract of the water-soluble acids of royal jelly. The differences observed in carbon dioxide evolution by young larvae on worker jelly and royal jelly are considered to be an expression of the initiation of female dimorphism. An hypothesis of nutritional balance is advanced to account for this dimorphism.

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