Almost one-third of all proteases can be classified as serine proteases, named for the nucleophilic Ser residue at the active site. This mechanistic class was originally distinguished by the presence of the AspHis-Ser “charge relay” system or “catalytic triad”.1 The Asp-His-Ser triad can be found in at least four different structural contexts, indicating that this catalytic machinery has evolve...

Incubation of Drosophila salivary glands with radioactive diisopropyl fluorophosphate results in the uniform labeling of polytene chromosomes. Extensive labeling is seen only when chromosome squashes are prepared by a formaldehyde fixation procedure and not by standard acetic acid techniques. The labeling is inhibited in the presence of tosylphenylalanine chloromethyl ketone and phenylmethane s...

The recent coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome 2. COVID-19 was first reported in China (December 2019) and now prevalent across the globe. Entry of 2 into mammalian cells requires binding viral Spike (S) proteins to angiotensin-converting enzyme receptor. Once entered, S protein primed a specialized serine protease, transmembrane protease ...

BACKGROUND Serine proteases are major components of viper venom and target various stages of the blood coagulation system in victims and prey. A better understanding of the diversity of serine proteases and other enzymes present in snake venom will help to understand how the complexity of snake venom has evolved and will aid the development of novel therapeutics for treating snake bites. METH...

A number of complex processes are involved in Eimeria spp. survival, including control of sporulation, intracellular invasion, evasion of host immune responses, successful reproduction, and nutrition. Proteases have been implicated in many of these processes, but the occurrence and functions of serine proteases have not been characterized. Bioinformatic analysis suggests that the Eimeria tenell...

BACKGROUND Serine protease inhibitors act as modulators of serine proteases, playing important roles in protecting animal toxin peptides from degradation. However, all known serine protease inhibitors discovered thus far from animal venom belong to the Kunitz-type subfamily, and whether there are other novel types of protease inhibitors in animal venom remains unclear. PRINCIPAL FINDINGS Here...

Papillon-Lefèvre syndrome (PLS) results from mutations that inactivate cysteine protease cathepsin C (CTSC), which processes a variety of serine proteases considered essential for antimicrobial defense. Despite serine protease-deficient immune cell populations, PLS patients do not exhibit marked immunodeficiency. Here, we characterized a 24-year-old woman who had suffered from severe juvenile p...

The large and growing number of protease genes identified in the human genome, more than 560, reflects the complexity and relevance of these enzymes in multiple biological processes. As part of our studies on the human degradome--which is defined as the complete set of human protease genes--we have recently identified and cloned three complex polyserine proteases called polyserases. Polyserase-...

Toxicity of the extracellular products (ECP) and the lethal attribute of serine protease secreted by five pathogenic Vibrio alginolyticus strains from various sources in kuruma prawn Penaeus japonicus were studied. The ECPs of organisms originally isolated from diseased kuruma prawn or small abalone Haliotis diversicolor supertexta were more lethal (LD50 value of 0.48 or 0.41 microg protein/g p...

BACKGROUND The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear. OBJECTIVE We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation. METHODS IL-33 levels were quantifi...