Multifunctional Capacity Research Articles

ChemInform Abstract: Construction and Application of Heterocyclic N‐Oxides Possessing the Efficient and Multifunctional Photooxidation Capacity

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Evolution of Multifunctionalism in Enzymes: Specialist versus Generalist Strategies

New ideas concerning nonequilibrium thermodynamics and the concepts of dissipative structures are seen to have profound implications for evolutionary theory. In particular we stress the idea that organisms possess a hierarchy of adaptive possibilities, which result from a construction of nonlinear systems each capable of structural evolution. The genome carries information capable of many "morphogeneses, " as evidenced in enzyme variants. Data are presented to underline the important functional differences of these variants, and an argument put forward to support the latent multifunctional capacity of such macromolecules. A theoretical treatment of the evolution of multifunctional enzymes in the form of specialist versus generalist strategies is given, and it is shown that given considerations about volume swept, binding time, and cost of production, a generalist enzyme will do best in a dilute (or not spatially organized) system, and a specialist enzyme will do best in a dense or channelled environment. The implications of such strategies and stochastic softening of selection upon mutants are then discussed as an alternative to a strict neo-Darwinian approach to evolution.

Protease-activated protein kinase in rat liver plasma membrane

Upon limited proteolysis with trypsin, a cAMP and Ca 2+-independent protein kinase was produced from rat liver plasma membrane. This enzyme showed a multifunctional capacity and phosphorylated calf thymus histone and rat liver ribosomal proteins. The molecular weight was estimated to be 5.0 × 10 4. When plasma membrane was treated with a buffer containing Triton X-100, a proenzyme with a molecular weight of 8.4 × 10 4 was extracted. By tryptic digestion, the proenzyme was converted to an active protein kinase which was similar to the enzyme obtained by the direct digestion of membrane. However, this proenzyme phosphorylated H1 histone in the presence of Ca 2+ and phospholipid without proteolytic digestion. These results indicate the existence of a protease-activated protein kinase in rat liver plasma membrane and the proenzyme seems to be same as protein kinase C.

Modification of simian virus 40 large tumor antigen by glycosylation

The SV40-encoded transforming protein, large tumor antigen (T-ag), is multifunctional. Chemical modifications of the T-ag polypeptide may be important for its multifunctional capacity. T-ag is additionally modified by glycosylation. T-ag was metabolically labeled in SV40-infected cells with tritiated galactose or glucosamine, but not with mannose or fucose. The identity of glycosylated T-ag was established by immunoprecipitation with a variety of T-ag-specific antisera, including monoclonal antibodies. Incorporation of labeled sugar into T-ag was inhibited in the presence of excess unlabeled sugars, but not in the presence of excess unlabeled amino acids. Labeled monosaccharides could be preferentially removed from T-ag with a mixture of glycosidic enzymes. In addition, galactose was removed from purified T-ag by acid hydrolysis and identified as such by thin-layer chromatography. T-ag oligosaccharides were resistant to treatment with EndoH, and glycosylation was not inhibited by tunicamycin. Together, these data strongly suggest that T-ag is glycosylated. Several characteristics, including lack of mannose labeling, EndoH resistance, and tunicamycin resistance, suggest that T-ag is not an N-linked glycoprotein. Rather, these properties are more consistent with the identification of T-ag as an O-linked glycoprotein.

MEMBRANE BOUND INCLUSIONS IN EPIDERMAL PLASTIDS OF DEVELOPING SESAME LEAVES AND COTYLEDONS

SummaryEpidermal plastids of young sesame leaves and cotyledons contain amorphous membrane bound inclusions similar to those found in the mesophyll. However, unlike the mesophyll inclusions which disappear during chloroplast development, those in epidermal plastids persist, even in fully mature leaves where a limited grana fretwork system develops.The limiting membrane of the inclusion is apparently continuous with both the tubular complex of light grown tissues and the prolamellar body of etiolated tissues as well as with the granal and integranal membranes. These associations, as well as a decrease in staining density of the inclusion with maturation, are interpreted as indications of a precursor‐product relationship of the inclusion and a grana fretwork.The coexistence of both grana and the (presumably) proteinaceous inclusion manifest the multifunctional capacity of plastids.

A Modest Proposal for the Governance of America's Metropolitan Areas

Abstract The prospect of restructured governance in metropolitan areas remans an interesting, if illusive, option on the American urban scene. Four elements are suggested as necessary to a restructured metro government: authority, multifunctional capacity, a geographic scope approximating the urban area, and taxing powers. These four elements are seen as present to some degree in a small number of restructured metro areas. The experience of these areas is seen as leading to a model of metro governance which would be based on the following building blocks: local units of government able to make those decisions concerning the character and responsiveness of public services; areawide special purpose districts; metropolitan governing councils having authority to constrain local governments and special districts, with policy makers responsive to state government; and state government able to serve as an arbiter between local government and areawide governments. No matter what the efficiency of this model of metro governance, its test of utility must be its apparent relationship to relative achievement amongst a series of “quality of life” indicators pertinent to issues which are seen as responsive to areawide decision making.