Recently we have shown that the substrate specificity of catalytic IgG isolated from sera of patients with Hashimoto's thyroiditis, systemic lupus erythematosus (SLE), polyarthritis and hepatitis B for classic poly(N) homopolynucleotide substrates and for specific tRNA(Phe) with compact and stable structure was correlated with the type of disease. At the same time the cleavage specificity was different in comparison with that of all known human RNases. Here we investigated for the first time the hydrolysis by the IgGs isolated from sera of 31 patients with different diseases of the in vitro transcript of human mitochondrial tRNA(Lys) which has less stable structure as compared to tRNA(Phe). The level of activity was strongly dependent on the patient, but in general increased in the order: hepatitis B = Hashimoto's thyroiditis < SLE. The pH dependencies and various salts effects also varied for Abs from the sera of different patients. Nevertheless, the RNase activity of all IgGs was specifically stimulated by Mg(2+) ions, that essentially completely suppress the activity of all known human RNases. In contrast to the classical substrates, no correlation between patient's IgG cleavage specificity and a specific disease was revealed; each patient demonstrated an individual repertoire of polyclonal RNA-hydrolyzing IgGs independently of the disease.
Download full-text PDF |
Source |
---|
Plant Physiol
January 2025
Leibniz Universität Hannover, Department of Molecular Nutrition and Biochemistry of Plants, Herrenhäuser Str. 2, 30419 Hannover, Germany.
The vacuole is an important site for RNA degradation. Autophagy delivers RNA to the vacuole, where the vacuolar T2 RNase Ribonuclease 2 (RNS2) plays a major role in RNA catabolism. The presumed products of RNS2 activity are 3'-nucleoside monophosphates (3'-NMPs).
View Article and Find Full Text PDFGlycoconj J
January 2025
School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
Chondroitin sulphate (CS) is a sulphated glycosaminoglycan (GAG) polysaccharide found on proteoglycans (CSPGs) in extracellular and pericellular matrices. Chondroitinase ABC (CSase ABC) derived from Proteus vulgaris is an enzyme that has gained attention for the capacity to cleave chondroitin sulphate (CS) glycosaminoglycans (GAG) from various proteoglycans such as Aggrecan, Neurocan, Decorin etc. The substrate specificity of CSase ABC is well-known for targeting various structural motifs of CS chains and has gained popularity in the field of neuro-regeneration by selective degradation of CS GAG chains.
View Article and Find Full Text PDFJ Mol Evol
January 2025
Department of Plant and Soil Sciences, 311 Plant Science Building, University of Kentucky, Lexington, KY, 40546-0312, USA.
Amino acid racemases catalyze the interconversion of L- and D-amino acids, maintaining intracellular levels of both D- and L-amino acids. While alanine and glutamate racemases are widespread in bacteria, serine racemase (SerR) is predominantly found in animals. Recently, homologs of animal SerR were reported in some bacterial genomes, but their evolutionary distribution and functional roles remain poorly understood.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
January 2025
Advanced Analysis Center, National Agriculture and Food Research Organization, 2-1-2 Kannondai, Tsukuba, Japan.
The aromatic aldehyde synthase (AAS), PonAAS2, from the gall-inducing sawfly has been identified as a biosynthetic enzyme for indole-3-acetic acid (IAA), a key molecule of the plant hormone auxin, which is thought to play a role in gall induction. Unlike other insect AASs that convert Dopa, PonAAS2 uniquely converts L-tryptophan (Trp) into indole-3-acetaldehyde, a precursor of IAA. In this study, an examination of AAS enzymes from various insect species revealed that the ability to convert Trp has been acquired in only a very limited taxonomic group.
View Article and Find Full Text PDFCommun Biol
January 2025
Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
Galactosides are major carbohydrates that are found in plant cell walls and various prebiotic oligosaccharides. Studying the detailed biochemical functions of β-galactosidases in degrading these carbohydrates is important. In particular, identifying β-galactosidases with new substrate specificities could help in the production of potentially beneficial oligosaccharides.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!