Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The binding of all-trans-retinoic acid (all-trans RA) to specific cytosol proteins and the effects of retinoids on procollagen synthesis were studied in chick-embryo tendon cells. For the receptor assay, tendon cytosols were incubated with [3H]all-trans-RA in the presence or absence of 100-fold excess of nonlabeled all-trans-RA up to 20 hr at +4 degrees and unbound retinoid was removed by charcoal-dextran treatment or by gel filtration chromatography. The results indicated that chick-embryo tendon cells contained cellular retinoic acid binding protein (CRABP). The binding of [3H]all-trans-RA could be displaced by 13-cis-retinoic acid, but not by retinol or etretinate. In contrast no CRABP could be found in cartilage cells isolated from sterna or in whole sterna. The treatment of tendon cytosol with proteases (pronase, trypsin, chymotrypsin) abolished the specific binding of [3H]all-trans-RA. Gel filtration studies on Sephadex G-100 indicated an apparent molecular weight of 14,500-15,000 daltons for the all-trans-retinoic acid binding protein. All-trans-RA markedly decreased procollagen synthesis in isolated chick-embryo tendon cells, the inhibition being concentration dependent; the decrease was about 58% of the control in the presence of 10(-5) M all-trans-RA. Similar decrease was noted with 13-cis-RA and etretinate, while retinol was less effective. In isolated cartilage cells the dose of 10(-5) M of all-trans-retinoic acid decreased drastically total protein and collagen synthesis. The mannosylation of procollagen, the conversion of procollagen to collagen and the size of procollagen chains were not significantly affected. The results of the present study indicate that CRABP is not expressed in sterna of chick-embryos, and in contrast high levels of CRABP could be found in tendons. However, retinoids modulated collagen synthesis in both tissues. Thus it is possible that retinoids can affect the metabolism of different collagen types also in clinical use.
 ...
PMID:Demonstration of cellular retinoic acid binding protein (CRABP) in chick embryo tendon cells and effects of retinoids on collagen synthesis in tendon and sterna. 302 Nov 69

Mouse embryonic stem cells (ESCs) can be induced to form pancreatic exocrine enzyme-producing cells in vitro in a stepwise fashion that recapitulates the development in vivo. However, there is no protocol for the differentiation of pancreatic-like cells from human ESCs (hESCs). Based upon the mouse ESC model, we have induced the in vitro formation of pancreatic exocrine enzyme-producing cells from hESCs. The protocol took place in four stages. In Stage 1, embryoid bodies (EBs) were formed from dissociated hESCs and then treated with the growth factor activin A, which promoted the expression of Foxa2 and Sox17 mRNAs, markers of definitive endoderm. In Stage 2, the cells were treated with all-trans retinoic acid which promoted the transition to cells that expressed gut tube endoderm mRNA marker HNF1b. In Stage 3, the cells were treated with fibroblast growth factor 7 (FGF7), which induced expression of Pdx1 typical of pancreatic progenitor cells. In Stage 4, treatment with FGF7, glucagon-like peptide 1, and nicotinamide induced the expression amylase (AMY) mRNA, a marker for mature pancreatic exocrine cells. Immunohistochemical staining showed the expression of AMY protein at the edges of cell clusters. These cells also expressed other exocrine secretory proteins including elastase, carboxypeptidase A, chymotrypsin, and pancreatic lipase in culture. Production of these hESC-derived pancreatic enzyme-producing cells represents a critical step in the study of pancreatic organogenesis and in the development of a renewable source of human pancreatic-like exocrine cells.
 ...
PMID:Pancreatic exocrine enzyme-producing cell differentiation via embryoid bodies from human embryonic stem cells. 2168 56