The relationship between rate of photosynthesis and CO 2 concentration has been reinvestigated using isolated spinach ( Spinacia oleracea ) chloroplasts. The apparently low CO 2 concentration required for half-maximal photosynthesis is shown to result partly from a ceiling imposed by electron transport. In double reciprocal plots of rate against CO 2 concentration, this ceiling results in departures from linearity at high CO 2 concentrations. If these rate limitations are disregarded in extrapolation the “true” CO 2 concentration required for half maximal carboxylation by intact chloroplasts is approximately 46 μ m (CO 2 ). When assayed under comparable conditions, ribulose bisphosphate carboxylase from these chloroplasts also shows an apparent K m (CO 2 ) of approximately 46 μ m , suggesting that its characteristics are not modified by extraction. An improved assay for ribulose bisphosphate carboxylase yielded rates of carboxylation considerably higher than those previously reported, the highest maximal velocities recorded approaching 1000 μmoles CO 2 fixed mg −1 chlorophyll hr −1 at 20 C. With such K m and V max , values the carboxylase would be able to achieve, at concentrations of CO 2 less than atmospheric, rates of CO 2 fixation equal to those displayed by the parent tissue or by the average plant under favorable conditions in its natural environment.
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera