Lysyl hydroxylase (EC 1.14.11.4) and glucosyltransferase (EC 2.4.1.66) are enzymes involved in post-translational modifications during collagen biosynthesis. We reveal in this paper that the protein produced by the cDNA for human lysyl hydroxylase isoform 3 (LH3) has both lysyl hydroxylase and glucosyltransferase (GGT) activities. The other known lysyl hydroxylase isoforms, LH1, LH2a, and LH2b, have no GGT activity. Furthermore, antibodies recognizing the amino acid sequence of human LH3 and those against a highly purified chicken GGT partially inhibited the GGT activity. Similarly, a partial inhibition was observed when these antibodies were tested against GGT extracted from human skin fibroblasts. In vitro mutagenesis experiments demonstrate that the amino acids involved in the GGT active site differ from those required for LH3 activity.Collagens are extracellular proteins found essentially in all tissues. They play a crucial role in maintenance of the structural integrity of tissues and in regulation of cellular behavior. The collagens, like other extracellular proteins, bind to growth factors and other regulatory components of cells and modulate cellular metabolism. To date, 19 genetically distinct collagen types have been identified (1-3). The collagen molecule is composed of three polypeptide chains, which coil around each other into a triple helical structure. Some of the collagen types, such as type I, II, and III collagens, have a rod-like structure without any interruptions in the helical region, whereas in the other types the triple-helical regions are interrupted with multiple short nonhelical sequences. Collagen molecules are aggregated in tissues into supramolecular structures such as fibrils, beaded filaments, or net-like or other kinds of structures depending on the type of collagen (3).The biosynthesis of collagen involves several post-translational modifications, which include hydroxylation of lysyl residues, galactosylation of hydroxylysyl residues, and glucosylation of galactosylhydroxylysyl residues. These reactions occur in the endoplasmic reticulum before triple helix formation. Hydroxylysine occurs in the Y position of the repeating XaaYaa-Gly triplet within the helical region of collagen molecules and also in the sequence of the nonhelical telopeptide regions of some collagen types when glycine is replaced either by serine or alanine (2, 4). The hydroxy groups of hydroxylysyl residues provide attachment sites for glycosyl residues, either the monosaccharide galactose or the disaccharide glucosylgalactose.The hydroxy groups also play a crucial role in the formation of inter-and intramolecular collagen cross-links. The biological role of the hydroxylysyl-linked carbohydrates, which are collagen-specific structures, is not clear. These carbohydrates point outward from the collagen helix and, thus, are located at the surface of the protein where they probably play an important role in lateral interactions between collagen triple helices and between collagen molecules and other extracellular ...

Our findings suggest that alcohol abuse results in diverse patterns of hematological effects and affects several cell lines. Therefore, in patients undergoing bone marrow examinations due to cytopenias, the probabilities for likely findings seem to be different between alcoholics and nonalcoholics. Information on ethanol consumption should be systematically included in the clinical assessment of such patients.

Alcoholic liver disease is associated with the generation of IgAs and IgGs against acetaldehyde-derived antigens and enhanced levels of both pro- and antiinflammatory cytokines, whereas elevated IgA, IL-6, and IL-10 characterize alcoholics without liver disease. These data suggest that immunological mechanisms may play a role in the sequence of events leading to liver disease in some patients with excessive drinking.

Background: Although alcohol abuse is known to cause a wide array of adverse effects on blood cell formation, the molecular mechanisms by which alcohol exerts its toxic actions remain poorly defined. We examine here the formation of acetaldehyde-derived protein modifications in erythrocytes and in their bone marrow precursors using antibodies specifically recognizing acetaldehyde-modified epitopes in proteins independently of the nature of the carrier protein. Materials and Methods: We studied 138 consecutive adult patients undergoing bone marrow aspiration due to macrocytosis (MCV values above 99 fL). Assessment included complete blood counts, morphologic review, assessment of alcohol consumption, and biochemical and immunocytochemical assays for acetaldehyde adducts. Results: There were 68 patients (49%) with a history of excessive alcohol consumption, 28 (20%) of whom were patients with severe dependence. The blood smears prepared from the alcoholic patients with macrocytosis also

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