The determination of enzyme activity or inhibition in intact living cells is a problem in the development of inhibitors for intracellular proteases. The production of fluorescent protoporphyrin IX (PpIX) from the nonfluorescent (N)-Gly/Pro-5-aminolevulinic acid (ALA) substrates was used to evaluate the prolyl/glycyl-specific dipeptidylpeptidase IV (DPPIV)-like and prolyloligopeptidase (POP)-like activities of human cells. The results demonstrated that whereas POP-like activity could be attributed to the actual POP, the DPPIV-like activity could be related to actual DPPIV only in one colon cell line. In the other breast and colon cell lines, DPPIV-like activity was intracellular and displayed by other prolyl-specific aminopeptidases. Our experiments also demonstrated the involvement of glycyl-specific proteases in the processing of ALA precursors. These observations have important consequences for the development and evaluation of selective inhibitors for these enzymes.
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http://dx.doi.org/10.1016/j.chembiol.2005.05.016 | DOI Listing |
Biophys J
January 2025
Theoretical Physics of Living Matter, Institute of Biological Information Processing and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany. Electronic address:
Translocation across barriers and through constrictions is a mechanism that is often used in vivo for transporting material between compartments. A specific example is apicomplexan parasites invading host cells through the tight junction that acts as a pore, and a similar barrier crossing is involved in drug delivery using lipid vesicles penetrating intact skin. Here, we use triangulated membranes and energy minimization to study the translocation of vesicles through pores with fixed radii.
View Article and Find Full Text PDFFront Sports Act Living
January 2025
Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, United States.
Introduction: In individuals with chronic post-stroke hemiparesis, slow walking speed is a significant concern related to inadequate propulsion of the paretic limb. However, an overlooked factor is this population's altered morphology of the Achilles tendon, which may compromise the propulsive forces by the paretic limb. This study aimed to explore changes in Achilles tendon morphology, including gross thickness and intra-tendinous collagen fiber bundle organization, following stroke-induced brain lesions.
View Article and Find Full Text PDFEJNMMI Radiopharm Chem
January 2025
Department of Nuclear Medicine and Medical Physics, Karolinska University Hospital, Stockholm, 171 76, Sweden.
Background: Beyond the use of conventional short-lived PET radionuclides, there is a growing interest in tracking larger biomolecules and exploring radiotheranostic applications. One promising option for imaging medium-sized molecules and peptides is ⁵⁵Co (T₁/₂ = 17.5 h, β⁺ = 76%), which enables imaging of new and already established tracers with blood circulation of several hours.
View Article and Find Full Text PDFFront Nephrol
January 2025
Department of Nephrology, Nephrology Vanderbilt Institute for Global Health (VIGH), Nashville, TN, United States.
Introduction: Antiretroviral therapy (ART) increases the life expectancy of persons living with HIV (PLWH), but not without potentially serious adverse effects. Tenofovir disoproxil fumarate (TDF) can cause nephrotoxicity, manifesting as acute kidney injury (AKI) that may persist after treatment discontinuation. Kidney injury biomarkers such as kidney injury molecule-1 (KIM-1), retinol-binding protein-4 (RBP-4), interleukin-18 (IL-18), and neutrophil gelatinase-associated lipocalin (NGAL) can aid early diagnosis and predict TDF-associated nephrotoxicity.
View Article and Find Full Text PDFJ Vis
January 2025
Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
Recent studies have suggested that autistic perception can be attributed to atypical Bayesian inference; however, it remains unclear whether the atypical Bayesian inference originates in the perceptual or post-perceptual stage or both. This study examined serial dependence in orientation at the perceptual and response stages in autistic and neurotypical adult groups. Participants comprised 17 autistic and 23 neurotypical adults.
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