Polypeptide N-acetylgalactosaminyltransferase-Associated Phenotypes in Mammals

Mucin-type O-glycosylation involves the attachment of glycans to an initial O-linked N-acetylgalactosamine (GalNAc) on serine and threonine residues on proteins. This process in mammals is initiated and regulated by a large family of 20 UDP-GalNAc: polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts) (EC 2.4.1.41). The enzymes are encoded by a large gene family (GALNTs). Two of these genes, GALNT2 and GALNT3, are known as monogenic autosomal recessive inherited disease genes with well characterized phenotypes, whereas a broad spectrum of phenotypes is associated with the remaining 18 genes. Until recently, the overlapping functionality of the 20 members of the enzyme family has hindered characterizing the specific biological roles of individual enzymes. However, recent evidence suggests that these enzymes do not have full functional redundancy and may serve specific purposes that are found in the different phenotypes described. Here, we summarize the current knowledge of GALNT and associated phenotypes.     

In-situ studies of catalysts by XAFS and Mössbauer spectroscopy

The unique advantages of XAFS and Mössbauer spectioscopy applied to studies of catalysts are discussed. These advantages include the importantin situ capability, as well as the possibility to provide information on X-ray amorphous materials. The successful use of the two techniques is demonstrated by examples of two important technical catalyst systems, hydrotreating and ammonia synthesis catalysts, representing supported and unsupported catalysts.

     

Room temperature palladium catalysed coupling of acyl chlorides with terminal alkynes

Conditions are reported for the facile, high-yielding coupling of acyl chlorides with terminal alkynes in a reaction involving palladium and copper iodide; the reaction is tolerant of a wide variety of acyl chlorides and terminal alkynes and provides a convenient one-pot route to acetylenic ketones.     

Biological conversion of coal gas to methane

Biological conversion of low-Btu coal synthesis gas to higher Btu methane was demonstrated using both pure co-cultures and/or adapted-mixed anaerobic bacteria.Peptostreptococcus productus metabolized coal gas to mainly acetate and CO₂. The co-cultures containing methanogens converted these products to methane. In mixed culture studies, CH₄ and small amounts of acetate were produced. Reactor studies using stirred-tank and immobilized cell reactors exhibited excellent potential to convert CO, CO₂ and H₂ to methane at higher gas flow rates. Gas retention times ranging from 0.7 to 2 hours and high agitation were required for 90 percent CO conversion in these systems. This paper also illustrates the potential of biological methanation and demonstrates the need for good mass transfer in converting gas phase substrates.     

Das Atomgewicht des Antimons

Ohne Zusammenfassung