Biological Chemistry 

About: Biological Chemistry is an academic journal published by De Gruyter. The journal publishes majorly in the area(s): Amino acid & Peptide sequence. It has an ISSN identifier of 1431-6730. Over the lifetime, 16349 publications have been published receiving 308016 citations. The journal is also known as: Biological chemistry online.

Untersuchungen uber die Harnstoffbildung im Tierkörper

Abstract: Das Hauptergebnis dieser Arbeit ist die Auffindung des Weges, auf dem im tierischen Organismus die Synthese des Harnstoffs aus Ammoniak und Kohlensaure verlauft. Die Harnstoffsynthese ist an das Vorhandensein von Ornithin gebunden, ohne das Ornithin in der Bilanz der Synthese verbraucht wird. Ornithin, Ammoniak und Kohlensaure treten unter Wasseraustritt zu einer Guanidinoverbindung — dem Arginin — zusammen [Reaktion (1)]. Arginin spaltet durch die Wirkungder Arginase Harnstoffab [Reaktion (2)] und liefert Ornithin zuruck, das wieder fur Reaktion (1) zur Verfugung steht.

Activation mechanisms of matrix metalloproteinases.

Abstract: Matrix metalloproteinases (MMPs), also called matrixins, function in the turnover of extracellular matrix components. These enzymes are considered to play important roles in embryo development, morphogenesis and tissue remodeling, and in diseases such as arthritis, periodontitis, glomerulonephritis, atherosclerosis, tissue ulceration, and in cancer cell invasion and metastasis. All MMPs are synthesized as preproenzymes and most of them are secreted from the cells as proenzymes. Thus, the activation of these proenzymes is one of the critical steps that leads to extracellular matrix breakdown. This review describes recent progress made to elucidate the activation mechanisms of pro-matrixins which include extracellular stepwise activation common to most proMMPs, cell surface activation of progelatinase A and procollagenase 3, and intracellular activation of prostromelysin 3 and pro-membrane-type-1 MMP.

Structural and functional diversity of connexin genes in the mouse and human genome

Abstract: Gap junctions are clustered channels between contacting cells through which direct intercellular communication via diffusion of ions and metabolites can occur. Two hemichannels, each built up of six connexin protein subunits in the plasma membrane of adjacent cells, can dock to each other to form conduits between cells. We have recently screened mouse and human genomic data bases and have found 19 connexin (Cx) genes in the mouse genome and 20 connexin genes in the human genome. One mouse connexin gene and two human connexin genes do not appear to have orthologs in the other genome. With three exceptions, the characterized connexin genes comprise two exons whereby the complete reading frame is located on the second exon. Targeted ablation of eleven mouse connexin genes revealed basic insights into the functional diversity of the connexin gene family. In addition, the phenotypes of human genetic disorders caused by mutated connexin genes further complement our understanding of connexin functions in the human organism. In this review we compare currently identified connexin genes in both the mouse and human genome and discuss the functions of gap junctions deduced from targeted mouse mutants and human genetic disorders.

Glutathione dysregulation and the etiology and progression of human diseases.

Abstract: Glutathione (GSH) plays an important role in a multitude of cellular processes, including cell differentiation, proliferation, and apoptosis, and as a result, disturbances in GSH homeostasis are implicated in the etiology and/or progression of a number of human diseases, including cancer, diseases of aging, cystic fibrosis, and cardiovascular, inflammatory, immune, metabolic, and neurodegenerative diseases. Owing to the pleiotropic effects of GSH on cell functions, it has been quite difficult to define the role of GSH in the onset and/or the expression of human diseases, although significant progress is being made. GSH levels, turnover rates, and/or oxidation state can be compromised by inherited or acquired defects in the enzymes, transporters, signaling molecules, or transcription factors that are involved in its homeostasis, or from exposure to reactive chemicals or metabolic intermediates. GSH deficiency or a decrease in the GSH/glutathione disulfide ratio manifests itself largely through an increased susceptibility to oxidative stress, and the resulting damage is thought to be involved in diseases, such as cancer, Parkinson's disease, and Alzheimer's disease. In addition, imbalances in GSH levels affect immune system function, and are thought to play a role in the aging process. Just as low intracellular GSH levels decrease cellular antioxidant capacity, elevated GSH levels generally increase antioxidant capacity and resistance to oxidative stress, and this is observed in many cancer cells. The higher GSH levels in some tumor cells are also typically associated with higher levels of GSH-related enzymes and transporters. Although neither the mechanism nor the implications of these changes are well defined, the high GSH content makes cancer cells chemoresistant, which is a major factor that limits drug treatment. The present report highlights and integrates the growing connections between imbalances in GSH homeostasis and a multitude of human diseases.