Recently, two new amino acids have been isolated from hydrolysates of bovine ligamenturn nuchae elastin by Partridge, Elsden, and Thomas (1). Further studies from the same laboratory (2) have shown the compounds to be structural isomers composed of a pyridinium ring with four side chains located at positions 1, 3, 4, and 5 (desmosine), as depicted in Fig. 1, or at positions 1, 2, 3, and 5 (isod...

Hormonal control of the initial step in hepatic gluconeogenesis from pyruvate was examined following acute administration of epinephrine, glucagon, or cortisol to adult rats. After hormonal treatment of the animals, the mitochondria were isolated for the study of pyruvate metabolism. When pyruvate and bicarbonate were the only substrates provided, mitochondrial fixation of carbon dioxide and pr...

The fact that individual protein subunits must have different regions in contact with neighboring subunits in any oligomeric assembly greater than a diier is considered in relation to the nature of subunit interactions. Binding equations for this model have been derived for various different tetrameric arrangements and compared with the equations given by other models. Methods of distinguishing...

The reactions of iodoacetate and bromoacetate with ribonuclease have already provided some information on the relationship between the chemical structure and the catalytic a(*tivity of the enzyme. It is the purpose of this and the following paper to extend this information. In earlier studies, Gundlach, Stein, and Moore (1) showed that although alkylation at lysine, mrthioninc, or histidine res...

In their comprehensive work on 2acetylaminofluorenel (Fig. 1) the Weisburgers and Morris (l-4) have identified six phenolic metabolites of this carcinogen in the urine of adult rats. During recent studies (5) on this compound we have encountered a new acidic urinary metabolite. This metabolite is of interest since its excretion is greatly reduced by administration of a-methylcholanthrene, a pot...

The experiments with isotopes of the group at the Carnegie Institution of Washington laboratory (1) led to the concept of the aspartic acid family of amino acids. It was shown that, in Escherichiu co.%, aspartic acid contributes carbon to form all or part of the carbon skeleton of threonine, methionine, isoleucine, lysine, and diaminopimelic acid. The intermediates in the transformation of aspa...

A new procedure has been described for the isolation and purification of ascorbate oxidase from green zucchini squash (Cucurbita pepo meduttosa). The new purification method achieves a more than ZOO-fold purification with about a 14% recovery of the total activity present in the crude juice. The purified enzyme preparations have been found to be homogeneous by the criteria of ultracentrifugal a...