Pepsin D. A minor component of commercial pepsin preparations.
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ABSTRACT:
SUBMITTER: Lee D
PROVIDER: S-EPMC1271214 | biostudies-other | 1967 Sep
REPOSITORIES: biostudies-other
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Project description:Commercially available porcine pepsin preparations have been used for the production of chitooligosaccharides with various biomedical activities. However, the origin of this activity is not well understood. Here we show that the chitosan-degrading activity is conferred by residues with chitinolytic activity of truncated forms of acidic chitinase (Chia) persisting in the pepsin preparation. Chia is an acid-stable and pepsin-resistant enzyme that degrades chitin to produce N-acetyl-D-glucosamine dimer. We found that Chia can be truncated by pepsin under stomach-like conditions while maintaining its enzymatic activity. Similarly to the full-length protein, truncated Chia as well as the pepsin preparations digested chitosan with different degrees of deacetylation (DD: 69-84%) with comparable degradation products. The efficiency was DD-dependent with a marked decrease with higher DD, indicating that the chitosan-degrading activity in the pepsin preparation is due to the chitinolytic activity rather than chitosanolytic activity. We suggest that natural or recombinant porcine Chia are suitable for producing chitooligosaccharides for biomedical purposes.
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2021-04-19 | GSE143392 | GEO
Project description:BACKGROUND:Commercial herbal medicines (CHMs) marketed as immune boosters are gaining wide popularity in South Africa, in the absence of control and regulatory guidelines. These commercially packaged and labelled herbal preparations, acquired in various retail outlets, are used without consulting either a conventional health provider or a traditional health practitioner. Although they are indicated for immune-boosting purposes, they might exert many other beneficial and unwanted effects on physiological systems. Platelets are crucial in haemostasis and important for the immunological system. The aim was to investigate the effect of the CHMs used to strengthen the immune system on the activity of human platelets. METHODS:Six CHMs commonly used as African traditional medicines in Pretoria, South Africa, were tested for their effects on healthy, isolated human platelets, using a bioluminescence method. The tested herbal medicines were Intlamba Zifo™, Maphilisa™ Herbal medicine, Matla™ African medicine for all diseases, Ngoma™ Herbal Tonic Immune Booster, Stametta™ Body Healing Liquid, and Vuka Uphile™ Immune Booster and serial-diluted standards of each from 10 to 10,000 times. The luminol-enhanced luminescence activity of the platelets was measured after incubation with the herbal medicines and activation with phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP). RESULTS:Five herbal medicines, namely Intlamba Zifo™, Maphilisa™ Herbal medicine, Matla™ African medicine for all diseases, Stametta™ Body Healing Liquid, and Vuka Uphile™ Immune Booster exerted comparable weak inhibitory effects on both PMA and fMLP-induced platelets, which were concentration dependent at high doses, and inversely related to concentration at low doses. Intlamba Zifo™, Matla™ African medicine for all diseases, Stametta™ Body Healing Liquid, and Vuka Uphile™ exhibited weak, but non-systematic stimulatory effects at low doses, which were not statistically significant. Ngoma™ Herbal Tonic Immune Booster had weak, inhibitory effects at high doses and weak stimulatory effects that were inversely related to concentration at low doses. CONCLUSION:The findings suggest a potential beneficial role of the CHMs in the suppression of platelets' reactivity and in enhancing the immune system. Caution, however, should be exercised as platelet inhibition and stimulation predispose to the risk of bleeding and thrombosis, respectively.
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