S-adenosylmethionine (SAM) is the substrate used in the methylation of homogalacturonan (HGA) in the Golgi apparatus. SAM is synthesized in the cytosol, but it is not currently known how it is then transported into the Golgi. In this study, we find that HGA methyltransferase is present in Golgi-enriched fractions and that its catalytic domain faces the lumen of this organelle. This suggests tha...

Deoxycytosine methylase (Dcm) enzyme activity causes mutagenesis in vitro either directly by enzyme-induced deamination of cytosine to uracil in the absence of the methyl donor, S-adenosylmethionine (SAM), or indirectly through spontaneous deamination of [5-methyl]cytosine to thymine. Using a Lac reversion assay, we investigated the contribution of the first mechanism to Dcm mutagenesis in vivo...

Previously, we identified an amplified gene in a stomach cancer cell line, KATO-III, and designated it K-sam. This gene was later found to be identical with a gene for a receptor tyrosine kinase, bek/FGFR2. One of the characteristics of the K.sam gene is structural diversity of its transcripts; K-sam complementary DNA (cDNA) cloned from human brain (K-sam-I) has a completely different sequence ...

Previously, we identified an amplified gene in a stomach cancer cell line, KATO-III, and designated it K-sam. This gene was later found to be identical with a gene for a receptor tyrosine kinase, bek/FGFR2. One of the characteristics of the K.sam gene is structural diversity of its transcripts; K-sam complementary DNA (cDNA) cloned from human brain (K-sam-I) has a completely different sequence ...

This study is executed to develop probiotics which produce S-adenosyl-L-methionine (SAM), a methyl group donor of the 5-methyltetrahydrofolate methylation reaction within the animal cell. SAM is an essential substance for the synthesis, activation, and metabolism of hormones, neurotransmitters, nucleic acids, phospholipids, and cell membranes of animals. The SAM is also known as a nutritional s...

OBJECTIVES We set out to determine if intraoperative pre-bypass transoesophageal echocardiography could assist in predicting which patients are at greatest risk for systolic anterior motion (SAM) after mitral valve repair (MVR). METHODS Three hundred and seventy-five consecutive patients who underwent reconstructive MVR surgery for degenerative disease were included. Data were collected using...

To understand how S-adenosylmethionine (SAM) concentrations fluctuate in normal and cancerous cells, particularly normal and cancerous liver cells, we have developed a novel real-time immunoassay to simultaneously measure methionine adenosyltransferase (MAT) activity and SAM levels. This method integrates the MAT-catalyzed reaction of L-Met and ATP to produce SAM and a highly sensitive immunoas...

The S-adenosylmethionine-1 (SAM-I) riboswitch mediates expression of proteins involved in sulfur metabolism via formation of alternative conformations in response to binding by SAM. Models for kinetic trapping of the RNA in the bound conformation require annealing of nonadjacent mRNA segments during a transcriptional pause. The entropic cost required to bring nonadjacent segments together shoul...

The shoot apical meristem (SAM) ensures continuous plant growth and organogenesis. In LD 30 °C, plants lacking AtFTSH4, an ATP-dependent mitochondrial protease that counteracts accumulation of internal oxidative stress, exhibit a puzzling phenotype of premature SAM termination. We aimed to elucidate the underlying cellular and molecular processes that link AtFTSH4 with SAM arrest. We studied At...

Severe necrotizing pancreatitis occurs in young female mice fed a choline-deficient and ethionine-supplemented (CDE) diet. Although the mechanism of the pancreatitis is unknown, one consequence of this diet is depletion of hepatic S-adenosylmethionine (SAM). SAM formation is catalyzed by methionine adenosyltransferases (MATs), which are encoded by liver-specific (MAT1A) and non-liver-specific (...