Review and Update of Casein Chemistry

Swaisgood, Harold E.

doi:10.3168/jds.s0022-0302(93)77645-6

Cited by 175 publications

(119 citation statements)

References 46 publications

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“…According to the amino acid sequence, casein is expected to contain more than a single cleavage site for TTR, whereas, only a single site was reported on apoAI 8 . The structure of casein contains several types of subunits which vary primarily in molecular weight, the isoelectric point, and the level of phosphorylation, leading to several secondary structures including an α-helix and a β-sheet of the molecule 30 . In contrast, the primary structure of apoAI is composed of several tandem repeats of 22 amino acids that form the amphipathic α-helical secondary structure 31 .…”

Section: Discussionmentioning

confidence: 99%

Proteolytic activity of Crocodylus porosus transthyretin protease and role of the terminal polypeptide sequences

Leelawatwattana¹,

Praphanphoj²,

Prapunpoj³

2016

ScienceAsia

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Human transthyretin (TTR), a recently identified protease, participates in the biology of high density lipoprotein and in the nervous system. In the present study, we determined whether TTR from a non-mammal Crocodylus porosus (crocTTR) has proteolytic activity and whether the N-and C-termini of the TTR polypeptide affect the proteolytic activity. The proteolytic activity of crocTTR and three chimeric crocTTRs: xenoN/crocTTR (crocTTR in which the N-terminal sequence was replaced with that of Xenopus laevis TTR), pigC/crocTTR (crocTTR in which the C-terminal sequence was replaced with that of Sus scrofa TTR), and xenoN/pigC/crocTTR (crocTTR in which the N-and C-terminal sequences were replaced with that of X. laevis TTR and S. scrofa TTR, respectively) were studied and compared. Using either casein or apoAI as a substrate, crocTTR had a lower proteolytic activity than human TTR. Replacing the C-terminal sequence of crocTTR increased the activity (casein: 1008 ± 36 pmol/min; apoAI: 231 ± 43 pmol/min), whereas replacing the N-terminal sequence decreased the activity (casein: 299 ± 26 pmol/min; apoAI: 31.5 ± 2.0 pmol/min). The activity of xenoN/pigC/crocTTR (casein: 502 ± 11 pmol/min; apoAI: 371 ± 23 pmol/min) was higher than those of crocTTR or xenoN/crocTTR, but similar to that of pigC/crocTTR. These results are the first to show the proteolytic activity of reptile TTR, and that the activity is changed when the N-and/or C-terminal amino acid sequences of the TTR subunit are changed.

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Section: Discussionmentioning

confidence: 99%

Proteolytic activity of Crocodylus porosus transthyretin protease and role of the terminal polypeptide sequences

Leelawatwattana¹,

Praphanphoj²,

Prapunpoj³

2016

ScienceAsia

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“…16 Briefly, sections were deparaffinized in xylene and rehydrated in graded alcohol and distilled water. The endogenenous peroxidase activity was blocked with 1% hydrogen peroxide in distilled water for 10 min, followed by washing in phosphate-buffered saline (PBS) and incubation with normal goat serum for 30 min to bind nonspecific antigens.…”

Section: Immunohistochemistrymentioning

confidence: 99%

Evidence of a novel biomarker, αs1-Casein, a milk protein, in benign prostate hyperplasia

Wang

et al. 2006

Prostate Cancer Prostatic Dis

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Benign prostate hyperplasia (BPH) is a common disease in elderly men. Although it is a nonmalignant disease, it has a significant detrimental impact on the quality of life in patients with latestage disease. Owing to the lack of specific markers, diagnosis of early-stage BPH has been proven unsuccessful. Recently, using two-dimensional electrophoresis, we identified a group of prostatic secretory proteins that are specifically produced by BPH cells (Xu et al., Electrophoresis 2003; 24: 1311). In this study, we investigated the potential diagnostic value of one of the secretory proteins, as1-Casein, in BPH by inmmunohistological staining of normal, BPH and prostate cancer tissues. We found that 90% (20 out of 22) of BPH tissues showed moderate to strong as1-Casein protein expression whereas none of the normal tissues (0 out of 10) and less than 10% of the prostate cancer tissues (3 out of 30) showed similar staining intensity. Our results suggest that as1-Casein may be a potential biomarker for early identification of BPH patients.

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“…On: Thu, 10 May 2018 06:41:02 their low-affinity, high-capacity binding of calcium (Aguanno & Ladenson, 1982;Swaisgood, 1993;Vorum et al, 1995;Farrell et al, 2002). To test whether the Ca 2+ -binding property is associated with the TSF activity, we surveyed a number of well-studied Ca 2+ -binding proteins, including high-and low-affinity Ca 2+ -binding proteins.…”

Section: Caseins In L Broth Function As Tsfsmentioning

confidence: 99%

“…As seen from Western blots in Fig. 7, ExoS secretion was only seen in the presence of L broth or casein in a concentrationdependent manner, further confirming the TSF function of the caseins.The casein complexes of all species contain two types of proteins: the a-and b-caseins, which bind calcium and aggregate, and k-casein, which does not bind calcium, but stabilizes the a-and b-caseins to yield the micelle or colloid (Swaisgood, 1993). Pure individual casein protein components, a-, b-and k-caseins, were obtained from a commercial source (Sigma) and tested for their TSF activities.…”

mentioning

confidence: 99%

Factors triggering type III secretion in Pseudomonas aeruginosa

et al. 2005

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The type III secretion system of Pseudomonas aeruginosa is tightly regulated by various environmental signals, such as low calcium and contact with the host cell. However, the exact signals triggering type III secretion are unknown. The present study describes the finding that secretion of P. aeruginosa type III effector molecules requires protein factors from serum and L broth, designated type III secretion factors (TSFs), in addition to the low-calcium environment. In the absence of TSF or calcium chelator EGTA, basal levels of type III effector molecules are accumulated intracellularly. Addition of TSF and EGTA together effectively triggers the secretion of pre-existing effector molecules in a short time, even before the active expression of type III genes; thus, active type III gene expression does not seem to be a prerequisite for type III secretion. A search for TSF molecules in serum and L broth resulted in the identification of albumin and casein as the functional TSF molecules. Although there is no clear sequence similarity between albumin and casein, both proteins are known to have a low-affinity, high-capacity calcium-binding property. Tests of well-studied calcium-binding proteins seemed to indicate that low-affinity calcium-binding proteins have TSF activity, although the requirement of low-affinity calcium-binding ability for the TSF activity is not clear. P. aeruginosa seems to have evolved a sensing mechanism to detect target cells for type III injection through host-derived proteins in combination with a low-calcium signal. Disruption of the bacterial ability to sense low calcium or TSF might be a valid avenue to the effective control of this bacterial pathogen. INTRODUCTIONThe remarkable ability of Pseudomonas aeruginosa to adapt to and thrive in a wide variety of environments contributes significantly to the ability of this bacterium to cause various human infections (Bodey et al., 1983;Holder, 1993;Pier, 2002). Unlike most human pathogens possessing highly restricted host ranges, P. aeruginosa is pathogenic not only to humans, but also to Caenorhabditis elegans, Drosophila and Arabidopsis thaliana (Rahme et al., 1995;D'Argenio et al., 2001;Aballay & Ausubel, 2002). This broad host range is contributed in part by the numerous virulence factors encoded by P. aeruginosa, including exotoxin A, phospholipase C, alkaline protease, elastase, alginate, pyocyanin, pili and non-pilus adhesins (Ramphal et al., 1991;Deretic et al., 1995;Lory & Strom, 1997;Vasil & Ochsner, 1999). P. aeruginosa, like many other Gram-negative animal and plant pathogens, also encodes a type III secretion machinery, where over 30 proteins assemble into a complex designed to deliver effector molecules directly into the cytoplasmic compartment of eukaryotic cells (Yahr et al., 1995;Frank, 1997). Injection of the bacterial effector molecules into the host cells results in various physiological changes, all of which seem to confer a survival advantage on the bacterial pathogen within the host environment (Hueck, 1998;Muller et al...

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Review and Update of Casein Chemistry

Cited by 175 publications

References 46 publications

Proteolytic activity of Crocodylus porosus transthyretin protease and role of the terminal polypeptide sequences

Proteolytic activity of Crocodylus porosus transthyretin protease and role of the terminal polypeptide sequences

Evidence of a novel biomarker, αs1-Casein, a milk protein, in benign prostate hyperplasia

Factors triggering type III secretion in Pseudomonas aeruginosa

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