Prolyl hydroxylase and other enzymes of collagen synthesis have been found in cloned cells, including epithelium, melanoma, liver, HeLa, pituitary, kidney, and neuroblastoma. The significance of collagen biosynthesis in nonfibroblastic cells lines is discussed.

Two enkephalin-containing polypeptides of 3600 and 4900 daltons have been isolated from extracts of bovine adrenal medulla, purified to homogeneity, and analyzed by a combination of automated Edman degradation and enzymatic time course hydrolysis. The 4900-dalton polypeptide contains two copies of enkephalin, one an internal [Metlenkephalin sequence, the other a [Leu]enkephalin sequence at the carboxyl terminus. Sequence analysis of the 3600-dalton polypeptide has not been completed, but the polypeptide has been shown to contain a single Met enkephalin sequence followed by an -Arg-Phe linkage that forms the carboxyl terminus of the molecule. On the basis of these and other findings, we propose that the above enkephalin-containig polypeptides are intermediates in the biosynthesis of the enkephalins and that they are generated by posttranslational processing from a large multivalent enkephalin precursor molecule, proenkephalin. The term "multivalent' is used to indicate a polypeptide with many identical functional sequences.

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