0000000000246802
AUTHOR
Jennifer S. Pollock
Identification of the NO Synthase isoforms Expressed in Human Neutrophil Granulocytes, Megakaryocytes and Platelets
SummaryUsing Western blot and fluorescent immunocytochemistry, NOS III (or ecNOS) and NOS II (or iNOS), but no NOS I (or ncNOS), were identified in preparations of human platelets. Reverse-transcription polymerase chain reactions (RT-PCR) demonstrated NOS III mRNA, but no NOS II mRNA (which is short-lived) and no NOS I mRNA in platelets. Immunofluorescent staining of human bone marrow smears showed the presence of NOS III, but not NOS I in megakaryocytes. A subpopulation of megakaryocytes also expressed NOS II. In preparations of human neutrophils, immunocytochemistry demonstrated NOS I in all cells, whereas no NOS III was detected. The few NOS II positive cells were characterized as contam…
Nitric oxide synthase isozymes. Characterization, purification, molecular cloning, and functions.
Three isozymes of nitric oxide (NO) synthase (EC 1.14.13.39) have been identified and the cDNAs for these enzymes isolated. In humans, isozymes I (in neuronal and epithelial cells), II (in cytokine-induced cells), and III (in endothelial cells) are encoded for by three different genes located on chromosomes 12, 17, and 7, respectively. The deduced amino acid sequences of the human isozymes show less than 59% identity. Across species, amino acid sequences for each isoform are well conserved (> 90% for isoforms I and III, > 80% for isoform II). All isoforms use L-arginine and molecular oxygen as substrates and require the cofactors NADPH, 6(R)-5,6,7,8-tetrahydrobiopterin, flavin adenine…
Nitric oxide synthase isozymes antibodies
Three isozymes of nitric oxide synthase (NOS) have been identified, cDNAs isolated and sequenced, and antibodies produced against each isozyme. Isozyme I (found primarily in central and peripheral neuronal cells), II (in cytokine-induced cells), and III (in endothelial cells) show less than 58% identity in the deduced amino acid sequences from humans. Many investigators have produced isozyme-specific antibodies and used these antibodies to locate these proteins in various cells and tissues. NOS-I is constitutively expressed, and the enzymatic activity is regulated by Ca2+ and calmodulin. The anti-NOS-I antibodies have allowed investigators to characterize non-adrenergic non-cholinergic neur…
[26] Isoforms of nitric-oxide synthase: Purification and regulation
Publisher Summary Nitric-oxide synthase (NOS) catalyzes the five-electron oxidation of L-arginine to the nitric oxide radical (.NO) and L-citrulline. Molecular oxygen is the cosubstrate of the enzyme. NO synthase activity has been found in a large variety of cells and tissues. The enzyme exists in several isoforms, three of which have been purified, characterized, and cloned. The activities of all three isoforms are found distributed between the soluble and particulate fractions of cells. Isoform I (from brain) and isoform II (from cytokine-induced macrophages) are mostly soluble proteins. Isoform III from endothelial cells is myristoylated and found predominantly in the particulate fractio…
Characterization of nitric oxide synthase isoforms expressed in different structures of the guinea pig cochlea.
Nitric oxide synthase (NOS) activity and NADPH diaphorase staining has previously been reported in mammalian cochlea. Here we demonstrate immunoreactivity for neuronal-type NOS I and endothelial-type NOS III in the cochlea of the guinea pig. NOS I immunoreactivity was seen in inner and outer hair cells, and spiral ganglion cells. Staining for NOS I was also shown in basal and intermediate cells of the stria vascularis, spiral ligament cells, and the media of vessels near the modiolus. An antibody to NOS III stained primarily vascular endothelial cells. Some NOS III immunoreactivity was also detected in spiral ganglion cells. An antibody to the inducible-type NOS II did not stain any structu…