Decarboxylation of L-Dopa and 5-Hydroxytryptophan in Dispersed Rat Pancreas Acinar Cells
Bibliographic record
Abstract
Amino acid decarboxylation activity in dispersed rat pancreas acinar cells and fractions derived by differential centrifugation of homogenate of these cells was studied. The rate of decarboxylation was measured by determining the rate of production of the [3H]-amine from [3H]-amino acid or the rate of production of 14CO2 from the [14C]-carboxy-labelled amino acid. Only the hydroxylated amino acids L-dopa and 5-hydroxytryptophan are decarboxylated by intact dispersed pancreas acinar cells or cell homogenates at all pH values and amino acid concentrations tested. The decarboxylase activity is located exclusively in the cell cytosol. Each substrate competitively inhibits the decarboxylation of the other and the decarboxylation of each is inhibited by NSD-1055. The estimated Km and Vmax are, for L-dopa, 4.8 X 10(-5) M and 2.5 nmol/mg protein/min and for 5-hydroxytryptophan, 2.9 X 10(-5) M and 0.3 nmol/mg protein/min. The pH optimum for 5-hydroxytryptophan decarboxylation is from 7.0-8.5 while that for L-dopa is 7.0. It is concluded that pancreas acinar cells possess a single aromatic amino acid decarboxylase specific for the hydroxylated amino acids L-dopa and 5-hydroxytryptophan, and which is similar in all properties studied to the aromatic amino acid decarboxylase found in several other mammalian tissues.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".