Tyrosinase prepared from plant, insect, and marine animal sources catalyzes the oxidation of tyrosine, dihydroxyphenylalanine (dopa), and various structurally similar compounds to darkly colored pigments (2). The enzymatic oxidation of many of the analogues of tyrosine and dopa often proceeds at a faster rate than for tyrosine and dopa themselves (2, 3). The investigation reported here was carr...

Fig. I. Absorption spectra of vitamin Ai (Ai), vitamin A2 (A2), subvitamin A (S), kitol (K), anhydrovitamin Ai (Ai'), anhydrovitamin A2 (AD and anhydrosubvitamin A (S'). to isolate kitol having the absorption maximum at 290 mμ.1> Furthermore, substances related to vitamin A such as anhydro vitam:ln A and subvitamin A have been confirmed in ordinary fish liver oils. Also in the whale liver oil, ...

The effect of temperature on the thermodynamic ionization constants of compounds with dipole moments greater than those of the a-amino acids has not heretofore been studied. In this paper results are given for glycylglycine and c-aminocaproic acid, two substances with similar dipole moments. Measurements are also included for aspartic acid, which has recently been studied at 25” in cells withou...

The prevalence of allergic diseases has increased all over the world during the last two decades. Dietary change is considered to be one of the environmental factors that cause this increase and worsen allergic symptoms. If this is the case, an appropriate intake of foods or beverages with anti-allergic activities is expected to prevent the onset of allergic diseases and ameliorate allergic sym...

ABSTRACT- In the past few decades, accumulation of heavy metals, such as lead (Pb), in soils has increased as a result of human activities.The environmental hazard associated with soil enrichment in heavy metals is related to their mobility and plant availability. Application of various materials such as humic may influence the amount of Pb taken up by plant. Four levels of each of liquid and s...

In this series of publications, the action of (2chloroethyl)trimethylammonium chloride’ and certain other structurally related compounds will be described as a class of plant growth substances. The growth of plants after treatment with certain of these chemical compounds will be published in subsequent articles?, 3 The most characteristic effect is the development of stockier plants with shorte...

Modelling substances in knowledge representation has to be diierent from the treatment of discrete objects. For example liquids need a diierent approach to individuation. We propose an ontology which represents physical states and other properties of substances in a uniform way. Based on this we describe how to model a hierarchy of actions that can deal with such substances. For these actions a...

Over a century ago, in 1835, Leopold Gmelin' prepared the substance tripotassium hydromelonate by heating potassium ferrocyanide with sulfur; he also made other salts of hydromelonic acid, and carried out analyses, which, however, were not sufficiently accurate to lead to correct formulas. He recognized the similarity of the substances to the group of nitrogen compounds discovered and named by ...