Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of cathepsin D, chymosin, pepsin and renin to produce endothelin-1 (ET-1) from proendothelin-1 (proET-1) was compared. No significant conversion was observed when proET-1 was incubated with up to 1 U of renin for 15 min at 37 degrees C. Cathepsin D generated, as well as degraded, ET-1 rapidly. Net production of ET-1 reached a maximum when 0.003 U of cathepsin D was used, and about 16% of the initial proET-1 was detected as ET-1 by HPLC. Pepsin up to 1 U converted proET-1 into ET-1 dose-dependently with a maximum of 71% conversion. A further increase of the amount of pepsin in the reaction mixture produced nonspecific cleavage of ET-1. Less than 10% of ET-1 remained in the presence of 15 U of pepsin. Chymosin also generated ET-1 dose-dependently, and a complete conversion was obtained at 1 U of enzyme. Greater than 1 U of chymosin only slightly degraded ET-1; at least 80% of ET-1 was still present when 15 U of chymosin was included in the assay. Other properties associated with the conversion of proET-1 into ET-1 by chymosin were investigated. Similar to authentic ET-1, the product of chymosin treatment caused contraction of isolated rabbit aortic rings, and pre-incubation of chymosin with pepstatin A abolished this contractile response.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Conversion of proendothelin-1 into endothelin-1 by aspartylproteases. 822 77

The amino acid permeability of the envelope of intact, functional spinach (Spinacia oleracea L.) chloroplasts was investigated by light scattering, volumetry and uptake of (14)C-labelled amino acids. The criterion for the functionally of the chloroplasts was their ability to reduce CO2, PGA and oxaloacetate in the light at high rates.Net uptake into the chloroplast interior of neutral amino acids such as alanine, glycine, serine, proline, threonine or valine occurred only at very low rates. The uptake was concentration dependent, indicating unspecific diffusion rather than carrier-mediated transport. The slowness of uptake is emphasized by the capability of neutral amino acids to provide osmotic support for intact chloroplasts during a considerable length of time. Back-exchange experiments also failed to indicate the existence of specific exchange carriers for the transport of neutral amino acids such as alanine or glycine through the envelope of intact chloroplasts. Dicarboxylic amino-acids are known to be taken up by the so-called dicarboxylate translocator. The same carrier was found to catalyze also the transfer of asparagine and glutamine.The data do not support current assumptions concerning fast carrier-mediated transport of neutral amino acids and their role in the transfer of carbon during photosynthesis.
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PMID:Amino acid permeability of the chloroplast envelope as measured by light scattering, volumetry and amino acid uptake. 2444 17