Sequential hydroxylation of lysine and glycosylation of hydroxylysine during the biosynthesis of collagen in isolated cartilage.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to J Rosenbloom.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The hydroxyproline and hydroxylysine in collagen are synthesized by an apparently unique pathway in which proline and lysine are hydroxylated after they are incorporated into a large polypeptide precursor of collagen called protocollagen. When the hydroxylation of protocollagen in isolated tissues is intermittently interrupted, hydroxylation can occur after complete polypeptides are released from ribosomal complexes. Cartilage from chick embryos was incubated with the iron chelator alpha,alpha'-dipyridyl for 2 hours to inhibit protocollagen hydroxylase, and then the inhibition was reversed by transferring the tissues to medium containing ferrous iron and no alpha,alpha'-dipyridyl. "Pulse labeling" of the tissues during these two periods indicated that both the accumulated protocollagen and the polypeptides synthesized after reversal of the inhibition were hydroxylated at the same rate. Even when no measures are taken to inhibit the hydroxylation of protocollagen, most of the hydroxyproline in collagen is probably synthesized after complete protocollagen polypeptides are released from ribosomes.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
This study showed that the excised periodontal ligament from humans and hamsters actively synthesizes protein, as measured by 14C-proline incorporation, when incubated in vitro for periods of 30 minutes to six hours. However, only a small percentage of the protein synthesized was collagen.
This paper reports the results of a survey of more than 500 health benefit specialists about the advice they would give to medium-size and large employers on offering a tax-advantaged medical savings account (MSA). About 42 percent of respondents would recommend an MSA combined with a catastrophic health plan, while a third would advise against such a plan. When presented with a specific example of an MSA package that would be attractive to a large fraction of workers, the percentage of benefit specialists favoring adding an MSA option rose to 74 percent. However, respondents generally did not believe that most workers would choose the MSA, especially if the alternative were a health maintenance organization (HMO).
The early events in gout are not clear. In the present studies a chemotactic factor having a molecular weight of 8,400 has been identified in human gouty synovial fluid. Washed crystals from a tophus were shown to generate chemotactic activity when added to polymorphonuclear leukocytes. Amino acid analysis demonstrated this chemotactic factor to be relatively rich in glycine, serine, aspartic acid, glutamic acid and alanine. Evidence from canine experiments suggest that chemotactic activity may also be produced by synovial lining cells. The amount of chemotactic activity that can be demonstrated diminishes over time in joints repeatedly injected with urate crystals.