Async HttpWebResponse gets truncated If the response is of larger size

Question

I use the below code to get a json string from from a webservice in callback function and the request is requested using a "POST" method

HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;                   
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
Stream streamResponse = response.GetResponseStream();
StreamReader streamRead = new StreamReader(streamResponse);
string responseString = streamRead.ReadToEnd();

The above code works fare when response length is small, but in a specific case i receive a larger response which is around 1.35mb of size and i am receiving it truncated but i am able to view the complete response in browser and in terminal

Please help, thanks in advance